NCERT Class 9 Science English Past Paper PDF

Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 Q.1) Which of the following statements are Q.5) Which...

Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 Q.1) Which of the following statements are Q.5) Which of the following statements is correct? incorrect for metal? Statement 1: Physical state of a substance can be changed by changing its temperature a) They are poor conductors of electricity. Statement 2: Physical state of a substance can b) They are ductile. be changed by changing pressure c) They are malleable. d) All the above a) 1 only Q.6) Which of the following statements are true b) 2 only about metalloid? c) Both 1 and 2 1. Boron is a metalloid. d) Neither 1 nor 2 2. They are semi conductive in nature. Choose the correct option Q.2) Which one of the following statements is correct? 1. 1 only 2. 2 only 1. In solids, molecules are tightly packed. 3. Both 1 and 2 2. Force of attraction between molecules in 4. Neither 1 nor 2 solids is very weak Q.7) The process behind disappearing of a) 1 only naphthalene balls with time is known as: b) 2 only a) Melting c) Both statements are correct b) Condensation c) Sublimation d) Both statements are incorrect d) Matter Q.3) Which one of the following is correct Q.8) Tincture of iodine refers to: about gas? a) Iodine dissolved in milk b) Iodine dissolved in ethanol a) A gas does not have a fixed shape. c) Iodine dissolved in copper sulphate Solution b) A gas does not have fixed volume. d) Iodine dissolved in common salt. c) A gas can be compressed easily. d) All the above Q.9) Consider the following statements? 1. Bromine is a liquid non metal. 2. Carbon is a non metal. Q.4) Which one of the following statements is correct? Which of the above statements are correct? 1. If temperature of a solid substance is a) 1 Only increased, the force of attraction between its b) 2 only molecules will also increase c) Both 1 and 2 2. If temperature of a solid substance is d) Neither 1 nor 2 increased, the force of attraction between its molecules will decrease Q.10) Consider the following statements 1. Mixtures are constituted by more than one kind a) 1 only of pure form of matter b) 2 only 2. Noticeable boundaries of division are seen in c) Both 1 and 2 heterogeneous mixture d) Neither 1 nor 2 NCERT CLASS 9 1  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 Which of the above statements are correct? b) 3, 4 only c) 1, 4, 6 only a) 1 Only d) 2, 4, 7 only b) 2 only c) Both 1or 2 Q.14) Consider the following statements: d) Neither 1or 2 1. A Colloid is an intermediate between solution and suspension Q.11) consider the following statements; 2. Saturated solution is a solution where the 1. Suspensions are heterogeneous mixture while solvent is no more soluble without an increase Solution are homogenous. in temperature. 2. Solution diffuses rapidly while suspensions do not diffuse. Which of the above statements are incorrect? Which of the above statements are correct? a) 1 Only b) 2 only a) 1 Only c) Both 1 and 2 b) 2 only d) Neither 1 nor 2 c) Both 1 and 2 d) Neither 1 nor 2 Q.15) Which of the following will show the “Tyndall effect”? Q.12) Consider the following statements? a) Salt Solution 1. A process known as centrifugation is used to b) Milk separate butter from curd. c) Copper sulphate Solution 2. A process known as evaporation is used to d) Non Starch Solution. separate salt from sea water. Q.16) Consider the following statements: Which of the above statements are incorrect? 1. In a chemical substance the elements are a) 1 Only always present in definite proportions by mass. b) 2 only 2. Atoms are indivisible particles, which cannot c) Both 1 and 2 be created or destroyed in a chemical reaction. d) Neither 1 nor 2 Which of the above are correct? Q.13) Consider the following statements: a) 1 only 1. Cutting of trees b) 2 only 2. Rusting of almirah c) Both 1 or 2 3. Boiling of water to form steam d) none of the above 4. Passing of electric current through water and water breaking into hydrogen and oxygen Q.17) Consider the following statements; gases. 1. A molecule is in general a group of two or more 5. Dissolving common salt in water atoms. 6. Making a fruit salad with raw fruits, and 2. Atoms of the same element or of different 7. Burning of paper and wood elements can join together to form molecules. Which one of the above classify as chemical change. 3. The number of atoms constituting a molecule is known as its atomicity. a) 1,5,6 only Which of the above are correct? NCERT CLASS 9 2  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 a) 1 only b) 2 and 3 only Q.21) Consider the following statements about RUTHERFORD ATOMIC model, which of them c) 3 only was not explained by him; d) all of the above a) An atom consist of tiny positively charged Q.18) Consider the following statements: nucleus surrounded by negatively charged electrons. 1. A negatively charged ion is called an ‘cation’ b) Stability of an atom. 2. A positively charged ion is called an 'anion'. c) Most of the mass atom is concentrated in the nucleus. Which of the above are incorrect? d) The number of electrons and protons are equal a) 1 only in an atom. b) 2 only c) Both 1 and 2 Q.22) Consider the following statements; d) None of the above 1. Bohr discovered the neutrons. Q.19) Consider the following statements: 2. Neutrons are present in the nucleus of all the atoms. 1. The molecular mass of a substance is the sum of the atomic masses of all the atoms in a Which of the above are incorrect? molecule of the substance. a) 1 only 2. One mole of any species is that quantity in b) 2 only number having a mass equal to its atomic or molecular mass in grams. c) both 1 and 2 Which of the above are correct? d) none of the above a) 1 only b) 2 only Q.23) Consider the following statements: c) Both 1 and 2 1. Electrons in an atom are arranged in different shells/orbits. d) None of the above 2. Bohr - Bury scheme explained that outermost shell of an atom has maximum of 8 electrons. Q.20) Consider the following statements; Which of the above are correct? 1) The radiations that are positively charged are a) 1 only canal rays. b) 2 only 2) An atom with both electron and proton with it will have a net positive charge. c) both 1 and 2 Which of the above are correct? d) none of the above a) 1 only b) 2 only Q.24) The Isotopes contain the same number of ____ and different number of ____ c) Both 1 and 2 a) neutron, proton d) None of the above NCERT CLASS 9 3  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 b) electron, proton a) 1 and 3only c) proton ,neutron b) 2 and 3 only d) neutron, proton c) 3 only d) All of the above Q.25) Consider the following statements; 1. An isotope of uranium is used as a fuel in Q.28) Consider the following statements. nuclear reactors. 1. If the medium surrounding the cell has a higher 2. An isotope of cobalt is used in the treatment of water concentration than the cell, the cell will cancer. lose water. 3. An isotope of iodine is used in the treatment of 2. If the medium has a lower concentration of goitre. water than the cell, the cell will gain water. Which of the above are correct? Which of the above are incorrect? a) 1 and 3only a) 1 only b) 2 and 3 only b) 2 only c) 3 only c) both 1 and 2 d) All of the above d) none of the above Q.26) Consider the following statements: Q.29) CONSIDER THE FOLLOWING FUNCTIONS ABOUT GOLGI APPARATUS: 1. Isobars are atoms having the same mass number but different atomic numbers. 1. It stores, modify the products in vesicles. 2. Isotopes are atoms of the same element, which 2. It is also involved in the formation of have different mass numbers. lysosomes Which of the above are incorrect? Which of the above are incorrect? a) 1 only a) 1 only b) 2 only b) 2 only c) Both 1 and 2 c) both 1 and 2 d) None of the above d) none of the above Q.27) Consider the following statements: Q.30) Consider the following: 1. All cells come from pre-existing cells. 1. Lysosomes are a kind of waste disposal system 2. All cells are found to have the same organelles. of the cell. 3. Plasma membrane is the outermost covering of 2. Mitochondria have their own DNA and the cell that separates the contents of the cell ribosomes. from its external environment. Which of the above are correct? Which of the above are correct? a) 1 only NCERT CLASS 9 4  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 b) 2 only Q.34) Consider the following statements c) both 1 and 2 1. Stomata bring about the exchange of gases and transpiration. d) none of the above 2. 2 Plastids impart green color to the plants. Q.31) consider the following statements Which of the above are correct? 1. A tissue is defined as a cluster of cells which a) 1 only are dissimilar in structure and work together to perform a particular function. b) 2 only c) both 1 and 2 2. Plants and animals have same type of tissues. Which of the above are correct? d) none of the above a) 1 only Q.35) Consider the following statements: b) 2 only 1. Xylem can transport in both an upward and c) both 1 and 2 downward direction, while Phloem can transport only in upwards direction. d) none of the above 2. Xylem transports water and minerals while Q.32) Consider the following statements Phloem transports food and nutrients. 1. The growth of plants occurs only in certain Which of the statements given above is/are correct? specific regions. 2. Cells of meristematic tissue differentiate to a) 1 only form different types of permanent tissue. b) 2 only c) Both 1 and 2 Which of the above are correct? d) Neither 1 nor 2 a) 1 only Q.36) The term parthenogenesis refers to b) 2 only c) Both 1 and 2 a) the process by which different plant pigments are formed d) None of the above b) the phenomenon of night respiration in some plants c) the production of an embryo from a female Q.33) Consider the following statements gamete without male gamete d) the process by which insectivorous plants 1. The covering or protective tissues in the animal absorb nutrients from the trapped insects. body are epithelial tissues. 2. Blood is a type of connective tissue. Q.37) Consider the following statements Which of the above are correct? 1. Velocity cannot hold a negative value. a) 1 only 2. Speed can hold a negative value. b) 2 only Which of the statements given above is/are correct? c) Both 1 and 2 a) 1 only d) None of the above b) 2 only c) Both 1 and 2 NCERT CLASS 9 5  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 d) Neither 1 nor 2 Q.38) In the context of gravitational force and Q.41) Consider the following statements about electromagnetic force, consider the following plant pathogens. statements: 1. Bacteria as well as fungi can cause diseases in 1. While gravitational force is always attractive, plants. electromagnetic force can be both attractive 2. Pathogens can affect plants only after and repulsive. transmitting itself from the root to the shoots. 2. While gravitational force is only dependent on 3. Pathogen transmission cannot happen by the mass, the electromagnetic force is dependent on medium of water. both mass and charge. 3. While gravitational force is dependent upon the Select the Solution using the codes below. distance between the two bodies, the electromagnetic force is independent of it. a) 1 only b) 2 and 3 only Which of the statements given above is/are correct? c) 3 only d) 1, 2 and 3 a) 1 only b) 2 and 3 only Q.42) classify which one of these are aerosols? c) 1 and 3 only d) 1, 2 and 3 1. Fog 2. Automobile exhaust smoke Q.39) A highly trained singer can hit a note that 3. Clouds causes glass to shatter. Which of the following phenomenon exhibited by the sound waves is Select the Solution using the codes below. responsible for this? a) 1 only a) Reverberation b) 2 and 3 only b) Boundary behavior c) 2 only c) Resonance d) 1, 2 and 3 d) Interference Q.43) The elongation produced in a string that Q.40) Consider the following statements. hangs a stone inside a liquid jar 1. Tyndall effect can be observed when sunlight 1. Will increase with an increase in the density of passes through the canopy of a dense forest or the liquid filled in the jar when a fine beam of light enters a room through 2. Will increase if the mass of the earth were to a small hole. increase 2. Under the Tyndall effect, the longer wavelengths are more transmitted while the Which of the above is/are correct? shorter wavelengths are more diffusely reflected via scattering. a) a)1 only b) 2 only Which of the above is/are correct? c) Both 1 and 2 d) None of the above a) 1 only b) 2 only Q.44) Consider the following statements. c) Both 1 and 2 d) Neither 1 nor 2 NCERT CLASS 9 6  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 1. In a planetary orbit, the line joining the planet 1. Citrus canker and the Sun sweep equal areas in equal intervals 2. Rust of Wheat of time. 3. Yellow Vein Mosaic 2. The mean distance of a planet from the Sun is inversely proportional to its orbital period. Select the Solution using the codes below. Which of the above is/are correct? a) 1 and 2 only b) 2 and 3 only a) 1 only c) 1 only b) 2 only d) 1, 2 and 3 c) Both 1 and 2 d) None of the above Q48) Consider the following statements. Q.45) Which of the following are classified as 1. A wave is a disturbance that moves through a micronutrients for plants? medium when the particles of the medium set neighbouring particles into motion. 1. Iron 2. While transverse Sound waves cannot travel 2. Potassium without any medium, longitudinal sound waves 3. Sulphur do not require a medium to travel. 4. Copper Which of the above is/are correct? Select the Solution using the codes below. a) 1 only a) 3 only b) 2 only b) 4 only c) Both 1 and 2 c) 1 and 2 only d) None d) 1 and 4 only Q49) The ceilings of cinema halls, conference halls Q.46) Consider the following statements about the and concert halls are generally curved in order to: views of Ancient Indian philosophers and intellectuals. a) Reflect sound to all corners of the cinema hall. b) Create a phase difference in sound. 1. Maharishi Kanad, postulated that if we go on c) Create an echo effect in sound. dividing matter (padarth), we shall get smaller d) Increase volume of air for faster transmission and smaller particles and there will be no end to of sound. this division. 2. Vatsyayana gave the idea that the Universe is Q.50) Consider the following statements; an indivisible whole and atoms do not have any real existence. 1. Force of gravitation on a body is equal to the true weight of the body. Which of the above is/are correct? 2. A person standing in an elevator moving downward with the constant acceleration finds a) 1 only his weight less then equal. b) 2 only c) Both 1 and 2 Which of the above is/are incorrect? d) None a) 1 only Q47) Which of the following plant diseases are b) 2 only transmitted by air? c) Both 1 and 2 d) None NCERT CLASS 9 7  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 Q.51) A ball is rolling down a slope at a steady Which of the statements given above is/are correct? speed. Which of the following statements is correct? a) 1 only b) 2 only a. Frictional force is greater than the forward c) Both 1 and 2 force d) Neither 1 nor 2 b. There is an unbalanced force downwards. c. There are no forces acting on the ball. Q.56) Consider the following statements with d. The forces acting on the ball are balanced. reference to Prokaryotic and eukaryotic cells: Q.52) If the forces acting on an object are balanced, 1. In Prokaryotic cells, there is a well- defined then_____ nucleus and membrane-bound organelles. 2. In Eukaryotic cells, there is no well- defined a) the object will be in equilibrium nucleus and organelles are absent. b) the object will be in motion c) the object will have no acceleration Which of the statements given above is/are correct? d) the object loses its shape a) 1 only b) 2 only Q.53) Which of the following actions is/are c) Both 1 and 2 coordinated by the human brain? d) Neither 1 nor 2 1. Maintaining blood pressure 2. Regulating the heartbeat Q.57) Which among the following is known as the 3. Balancing the body powerhouse of the cell and has its own DNA and ribosomes? Select the Solution using the code given below. a) 1 only a) Mitochondria b) 2 and 3 only b) Nucleus c) 1 and 3 only c) Golgi Body d) 1, 2 and 3 d) Endoplasmic Reticulum Q.58) A body is falling freely under the action of Q.54) A man is pushing hard against a rigid brick gravity alone in a vacuum. Which one of the wall. In this context, which among the following is following is correct? correct? a) In the beginning, the kinetic energy of the body a) The internal energy used by the man is zero. is zero. b) The work done by the man is zero. b) As the body falls, the potential energy of the c) The force applied by the man is zero. body keeps increasing. d) None of the above c) The sum of potential energy and kinetic energy is different at all points. Q.55) Consider the following statements regarding d) All of the given statements are correct. the speed of sound in a different medium: Q.59) Which of the following statements are 1. Among the three states solid, liquid and correct about kinetic energy of a moving object? gaseous, sound travels fastest in the gaseous state. 1. It quantifies the amount of work the object 2. Sound travel travels faster in hot air than in cold could do as a result of its motion. air. 2. It is a scalar quantity. NCERT CLASS 9 8  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 3. It increases by a factor of four if the velocity of Which of the pairs given above are correctly the object is doubled. matched? Select the Solution using the code given below. a) 1 and 2 only b) 1 and 3 only a) 1 and 2 only c) 2 and 3 only b) 2 and 3 only d) 1, 2 and 3 c) 1 and 3 only d) 1, 2 and 3 Q.63) Arrange the following mediums in the increasing order of speed of sound in them at 25 Q.60) Arrange the following atomic particles in degree celsius. decreasing order of their respective atomic weights: 1. Steel 2. Water 1. Electron 3. Air 2. Proton 3. Neutron Select the Solution using the code given below. Select the Solution using the code given below. a) 1-2-3 b) 1-3-2 a) 1-3- 2 c) 2-3-1 b) 1-2 -3 d) 3-2-1 c) 3-2-1 d) 3-1-2 Q.64) Which of the following statements is/are correct regarding the sound waves? Q.61) With reference to the force of friction, consider the following statements: 1. Sound waves cannot travel through a vacuum. 2. The particles oscillate up and down about their 1. It is the resistive force acting between bodies mean position as the wave travels. that tends to oppose and damp out motion. 3. In a given medium under same physical 2. It works only on moving objects. conditions, the speed of sound changes 3. Friction force is greater if a rough surface is drastically with a change in frequency. involved than smooth surface. Select the Solution using the code given below. Which of the statements given above is/are correct? a) 1 only a) 1 and 2 only b) 2 and 3 only b) 3 only c) 1 and 3 only c) 1 and 3 only d) 1, 2 and 3 d) 1, 2 and 3 Q.62) Consider the following pairs: Q.65) Which of the following pairs are correctly Type of elements Atomic structure matched? 1. Isotopes : Equal atomic number Micro-organism Food Process 2. Isobars : Equal mass number 1. Bacteria : Curdling of Milk 2. Yeast : Bread leavening 3. Isotones : Equal number of neutrons 3. Fungi : Citric Acid production NCERT CLASS 9 9  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 Select the Solution using the code given below. Q.69) With reference to the transport of nutrients in plants, consider the following statements: a) 1 and 2 only b) 2 and 3 only 1. Xylem transports water-dissolved minerals c) 1 and 3 only unidirectionally from roots to the stems. d) 1, 2 and 3 2. Phloem transports organic and mineral nutrients bidirectionally between roots and Q.66) Which of the following diseases are caused stems. by protozoans? Which of the statement given above is/are correct? 1. Measles 2. Malaria a) 1 only 3. Diphtheria b) 2 only c) Both 1 and 2 Select the Solution using the code given below. d) Neither 1 nor 2 a) 1 only Q.70) Which among the following is/ are present b) 2 only only in plant cells? c) 1 and 3 only d) 2 and 3 only 1. Plastids 2. Vacuoles Q.67) Which among the following is/are tissues 3. Mitochondria present in the human body? Select the Solution using the code given below. 1. Blood 2. Cartilage a) 1 and 2 only 3. Skin b) 1 only c) 2 and 3 only Select the Solution using the code given below. d) 1, 2 and 3 a) 2 and 3 only Q.71) Which of the following are the constituents b) 1, 2 and 3 of a cell nucleus? c) 1 and 2 only d) 3 only 1. DNA 2. RNA Q.68) Which of the following are functions of 3. Protein blood? Select the Solution using the code given below. 1. Supply of carbon dioxide to living cells 2. Transportation of hormones to body parts a) 1 and 2 only 3. Supply of water to body parts b) 2 and 3 only c) 1 and 3 only Select the Solution using the code given below. d) 1, 2 and 3 a) 1 and 2 only b) 2 and 3 only c) 1 and 3 only Q.72) Consider the following pairs: d) 1, 2 and 3 Plant Part Function NCERT CLASS 9 10  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 1. Stomata : Transpiration c) Both 1 and 2 2. Carotenoids : Protect chrolophyll from d) Neither 1 nor 2 photodamage 3. Root hairs : Absorption of water Q.76) Which among the following phenomena explains the fact that we see lightning much before Which of the pairs given above is/are correctly we hear its thunder? matched? a) Light waves can travel in vacuum whereas a) 2 only sound waves cannot. b) 1 and 2 only b) Light waves travels faster than sound waves. c) 1 and 3 only c) Intensity of light waves is more than sound d) 1, 2 and 3 waves. d) Light waves are scattered more than sound waves. Q.73) The human voices are more clearly heard at Q.77) ____ is the process of growing two or dusk rather than during day time because of the more crops simultaneously on the same field in phenomenon of a definite row pattern. a) Refraction of sound a) Mixed cropping b) Diffraction of sound b) Intercropping c) Scattering of sound d) Dispersion of sound c) Crop rotation d) Both [a] and [c] Q.74) Consider the following statements: e) None of these 1. Bromine is the only non-metal which is liquid at room temperature. Q.78) Which of the following is the term used 2. Iodine is a lustrous non-metal. for the practice of bee culture? 3. Mercury is the only metal that occurs as liquid at room temperature. a) Sericulture b) Apiculture Which of the statements given above are correct? c) Agriculture a) 1 and 2 only d) Pisciculture b) 1 and 3 only c) 2 and 3 only Q.79) Which among the following can be the d) 1, 2 and 3 causes of cancer? Q.75) As compared with solids and liquids: 1. Non Ionizing Radiation 2. Virus 1. The force of attraction between the particles is 3. Tobacco maximum in gases. 2. The kinetic energy of the particles is minimum Select the Solution using the code given below. in gases. a) 3 only Select the Solution using the code given below. b) 1 and 3 only c) 1 and 2 only a) 1 only d) 1, 2 and 3 b) 2 only NCERT CLASS 9 11  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 Q.80) HH-260 and B-77 are breeds of: a) Lichens a) Cow b) Mosses b) Buffalo c) Ferns c) Fowls d) All the above d) Fish Q.85) Consider the following statements : Q.81) Which of the following statements is 1. The upward force acting on an object correct? immersed in the liquid is called buoyant force. 1. The quality value of honey depends upon flowers available. 2. Gravitational force effects buoyant force. 2. Apis dorsata is commonly known as little bee. Select the Solution using the code given below. a) 1 only b) 2 only a) 1 only c) Both 1 and 2 b) 2 only d) Neither 1 nor 2 c) Both 1 and 2 d) Neither 1 nor 2 Q.82) Consider the following statements: Q.86) Which of the following will require least 1. Planets like Venus and Mars have more than force to penetrate the piece of wood? 95% of carbon dioxide in the air. a) Sharp iron nail 2. Earth have a balanced composition of air. b) Blunt Iron rod Select the Solution using the code given below. c) Thin sheet of steel a) 1 only b) 2 only d) A Hammer c) Both 1 and 2 d) Neither 1 nor 2 Q.87) Consider the following statements: Q.83) Consider the following statement; 1. All objects experience a force of buoyancy when they are immersed in a fluid. The atmosphere of the earth is heated by 2. Objects having density more than that of the radiations which are mainly: liquid in which they are immersed, float on the surface of the liquid. a) Radiated by the sun Select the Solution using the code given below. b) Re-radiated by land a) 1 only c) Re-radiated by water b) 2 only d) Re-radiated by land and water c) Both 1 and 2 d) Neither 1 nor 2 Q.84) Which one among the following is used Q.88) Law of gravitation gives the gravitational as environment indicators or bio-indicators to force between: check the level of pollution? NCERT CLASS 9 12  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 d) Neither 1 nor 2 a) The earth and a point mass only. Q.92) Consider the following statements b) The earth and sun only. c) Any two bodies having some mass. 1. When a body thrown up, its kinetic energy gradually changes into potential energy. d) Two charged bodies only. 2. When a body falls from a certain height, its potential energy remains the same. 3. If two unequal masses have the same Q.89) Few characteristics of a quantity are momentum, then the heavier body possesses given below. Find out the name of the quantity. lesser kinetic energy. (i) It is zero at the centre of the earth. (ii) It is measures with a spring balance. Select the Solution using the code given below. (iii) It is a vector quantity. a) 3 only (iv) It's direction is towards the centre of the b) 1 and 3 only earth. c) 1 and 2 only a) Pressure d) 1, 2 and 3 b) Weight Q.93) Which of the following statements is NOT c) Mass correct? d) Kilogram a) The velocity of sound in the air decreases as the humidity increases. Q.90) Which one of the following is correct? b) The velocity of sound in air is independent of pressure. a) Universal gravitational constant (G) is a c) The velocity of sound in air increases with the vector quantity. increase of temperature. b) The value of G varies from place to place. d) The velocity of sound in air is not affected by the change in frequency. c) The value of G does not depend upon the nature of the medium between the two bodies. Q.94) Which of the following are processes of d) The value of G depends on the masses of the Nitrogen cycling? bodies. 1. Nitrogen fixation 2. Nitrification 3. Ammonification Q.91) Read the given statements and select the 4. Denitrification correct option. Select the Solution using the code given below: 1. If a light body and a heavy body possess the same momentum, the lighter body will possess a) 1 and 2 only more kinetic energy. b) 2 and 3 only 2. The kinetic energy of a body varies as the c) 3 and 4 only square of its velocity. d) 1, 2, 3 and 4 Which of the above statements is/are correct? Q.95) Liquified Petroleum Gas (LPG) is largely a) 1 only composed of b) 2 only c) Both 1 and 2 1. Methane NCERT CLASS 9 13  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 2. Ethylene 1. Disinfectants are applied to the living tissues to 3. Propane kill or prevent the growth of microorganisms. 4. Butane 2. Two per cent of iodine Solution in an alcohol- water mixture is called tincture of iodine. Select the Solution using the codes below. Which of the statements given above is/are correct? a) 1 only b) 2 and 3 only a) 1 only c) 1 and 4 only b) 2 only d) 3 and 4 only c) Both 1 and 2 d) Neither 1 nor 2 Q.96) The human body carries diverse communities of microorganisms, which are mainly Q.99) Consider the following statements: bacterial. These are referred to as “human microbiome”. This may include microorganisms 1. The blue colour of the sky is due to scattering such as of light by dust and water droplets present in the atmosphere. 1. Fungi 2. The reddish appearance of the Sun during 2. Archaea sunset and sunrise is due to the least scattered 3. Bacteria light reaching our eyes. 4. Protists 5. Viruses Which of the statements given above is/are correct? Select the Solution using the codes below. a) 1 only b) 2 only a) 1, 2 and 3 only c) Both 1 and 2 b) 2, 4 and 5 only d) Neither 1 nor 2 c) 1, 3 and 5 only d) 1, 2, 3, 4 and 5 Q.100) Which of the following does not make a criterion for classification of animals? Q.97) Consider the following statements a) Body cavity organisation 1. Forests help in purifying the air by absorbing b) Symmetry all kinds of pollutants. c) Cell wall structure 2. Plants in forest hold the soil thereby preventing d) Presence or absence of notochord soil erosion. 3. Transpiration helps to maintain the temperature of the surrounding and helps in the formation of clouds. Select the Solution using the code given below. a) 3 only b) 1 and 3 only c) 1 and 2 only d) 1, 2 and 3 Q.98) Consider the following statements: NCERT CLASS 9 14  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 Q.1) Ans: C absorb energy in the form of heat and their kinetic energy increases. Exp:  As the kinetic energy increases, the temperature  A substance’s state of matter is an extrinsic of the solid increases. As a result, the force of property, meaning it can be changed by its attraction between the molecules decreases and environment. Physical conditions like the molecules become more and more temperature and pressure affect state of matter. separated. This increases the potential energy Both temperature and pressure can be of the molecule and the particles leave their measured, and state changes can be observed. fixed positions and start moving more freely.  When thermal energy is added to a substance, its temperature increases, which can change its  At a particular temperature, the separation of state from solid to liquid (melting), liquid to gas the molecules increases by a large amount and (vaporization), or solid to gas (sublimation). the solid melts and converts into liquid. This When energy is removed, the opposite happens, particular temperature is the melting point of decreasing the substance’s temperature and that solid. The melting point of a pure substance turning it from liquid to solid (freezing), gas to is always higher than the melting point of that solid (deposition), or from gas to liquid substance when a small amount of an impurity (condensation). is present. Pressure also affects the melting  When the pressure exerted on a substance point of a substance. As the pressure on the increases, it can cause the substance to substance increases, the melting point condense. Decreasing pressure can cause it to decreases. vaporize. For some types of rock, decreasing pressure can also cause them to melt. Q.5) Ans: A Exp: Q.2) Ans: A Typical physical properties of metals: Exp:  high melting points  In the solid-state, the individual particles of a  good conductors of electricity substance are in fixed positions with respect to  good conductors of heat each other because there is not enough thermal  high density energy to overcome the intermolecular interactions between the particles. As a result,  malleable solids have a definite shape and volume and  ductile molecules are most tightly packed in solids Q.6) Ans: C .Most solids are hard, but some (like waxes) are Exp: relatively soft. Many solids composed of ions can also be quite brittle.  Metalloids are a very small group of elements found in the periodic table of elements along Q.3) Ans: D the zig-zag line that distinguishes metals from Exp: non-metals and is drawn from between boron Gases have neither fixed shape nor fixed volume. This and aluminium to the border between polonium is because of the weak intermolecular forces of and astatine. attraction in the gases. They take the shape and  Properties of Metalloids volume of the container in which they are placed.  Metalloids have properties that are intermediate between metals and non-metals. They have Q.4) Ans: B properties that are difficult to characterize. Exp: Melting point of a solid indicates the strength Physical Properties of Metalloids of the force of attraction between the particles of the solid. On heating a solid, its molecules NCERT CLASS 9 15  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 which a gas is directly converted into solid- State of matter Solid state  Camphor, Iodine, naphthalene, ammonium chloride etc. Luster Metallic luster Q.8) Ans: B Exp: Elasticity Brittle  Iodine is a powerful antiseptic. Its 2-3 per cent Solution in alcohol- water mixture is known as tincture of iodine. It is applied on wounds. Conductivity Semi-conductive in nature Iodoform is also used as an antiseptic for wounds. Boric acid in dilute aqueous Solution is weak antiseptic for eyes. Chemical Properties of Metalloids Q.9) Ans: C They are capable of forming Exp: Oxidation  Bromine is a non-metal and remain liquid at glasses room temperature. Bromine is a liquid because the intermolecular forces are strong enough so that it does not vaporise. When mixed with metals, they Alloys form alloys Q.10) Ans: C Metallic and non-metallic Allotropic allotrops are formed Exp: Homogeneous Heterogeneous mixture Few metalloids contract when mixture Melting they are melt Particles are All the particles are uniformly completely mixed and distributed can be distinguished with Compounds are formed when Compounds throughout the the bare eyes or under a they react with the halogens mixture microscope. Has a uniform Irregular composition Q.7) Ans: C composition Exp: No apparent Noticeable boundaries of boundaries of division.  Sublimation is the transition of a substance division from the solid phase to the gaseous phase without changing into the liquid phase. This process is an endothermic phase transition that occurs at a temperature and pressure below the triple point of the substance. Desublimation or Q.11) Ans: C deposition is the reverse of this process in Exp: NCERT CLASS 9 16  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 A Solution is a homogeneous mixture of two or  Dissolving more substances. Because of very small particle size, they do not scatter a beam of light passing common through the Solution. So, the path of light is not salt in water visible in a Solution and they diffuse easily while a suspension is a heterogeneous mixture in which the solute particles do not dissolve but remain suspended throughout the bulk of the medium. Particles of a suspension are visible to the naked eye. Q.12) Ans: d Q.14) Ans: d Exp: Exp:  A process known as centrifugation is used  Saturated Solution is that state in a Solution at to separate butter from curd. The process is a specific temperature when a solvent is no governed on the principle of density. more soluble without an increase in the  We can use the simple evaporation temperature. Example: Excess carbon leaves technique to separate salt from seawater. off as bubbles from a carbonated water Solution Distillation causes water to evaporate saturated with carbon , while A Colloid is an leaving solid salt behind, hence the intermediate between Solution and suspension. production of salt. It has particles of various sizes, that ranges  Sublimation can be used to separate between 2 to 1000 nanometers. Colloids can be camphor from salt as during the phase distinguished from Solution using the Tyndall change, camphor does not undergo a liquid effect. Tyndall effect is defined as the phase. scattering of light (light beam) through a colloidal Solution. Example: Milk, gelatine. Q.13) Ans: d Exp: Q.15) Ans:b The following is the classification into physical and chemical change Exp:  Tyndall effect is exhibited by only milk and Physical change Chemical change starch solution from the above-mentioned list of solutions. The Tyndall effect is the  Cutting the  Rusting of phenomenon in which the particles in a colloid trees almirah scatter the beams of light that are directed at  Boiling of  Passing of them. This effect is exhibited by all colloidal water to electric current solutions and some very fine suspensions. form steam through water, Therefore, it can be used to verify if a given  Melting of and water solution is a colloid. The intensity of scattered butter in a breaking into light depends on the density of the colloidal pan hydrogen and particles as well as the frequency of the incident oxygen gases light.  Making a fruit salad  Burning of  When a beam of light passes through a colloid, with raw paper and the colloidal particles present in the Solution do fruits wood not allow the beam to completely pass through. The light collides with the colloidal particles and is scattered (it deviates from its normal trajectory, which is a straight line). This NCERT CLASS 9 17  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 scattering makes the path of the light beam Q.18) Ans: C visible. Exp: Q.16) Ans: c  Compounds composed of metals and non- metals contain charged species. The charged  explanation; According to Dalton’s atomic species are known as ions. An ion is a charged theory, all matter, whether an element, a particle and can be negatively or positively compound or a mixture is composed of small charged. A negatively charged ion is called an particles called atoms. The postulates of this ‘anion’ and the positively charged ion, a theory may be stated as follows: All matter is ‘cation’. Take, for example, sodium chloride made of very tiny particles called atoms. (NaCl). Its constituent particles are positively  Atoms are indivisible particles, which cannot charged sodium ions (Na+) and negatively be created or destroyed in a chemical reaction. charged chloride ions (Cl–).  Atoms of a given element are identical in mass Q.19) Ans: C and chemical properties.  Atoms of different elements have different Exp: masses and chemical properties.  The molecular mass of a substance is the sum  Atoms combine in the ratio of small whole of the atomic masses of all the atoms in a numbers to form compounds. molecule of the substance. It is therefore the relative mass of a molecule expressed in atomic  The relative number and kinds of atoms are mass units (u) for example, constant in a given compound.  Atomic mass of hydrogen = 1u, oxygen = 16 u. Q.17) Ans: d So the molecular mass of water, which contains two atoms of hydrogen and one atom of oxygen Exp: is = 2 × 1+ 1×16 = 18 u.  A molecule is in general a group of two or more  The quantity of a substance can be atoms that are chemically bonded together, that characterised by its mass or the number of is, tightly held together by attractive forces. A molecules. But, a chemical reaction equation molecule can be defined as the smallest particle indicates directly the number of atoms or of an element or a compound that is capable of molecules taking part in the reaction. an independent existence and shows all the Therefore, it is more convenient to refer to the properties of that substance. Atoms of the same quantity of a substance in terms of the number element or of different elements can join of its molecules or atoms, rather than their together to form molecules. The molecules of masses. So, a new unit “mole” was introduced. an element are constituted by the same type of One mole of any species ( atoms, molecules, atoms. Molecules of many elements, such as ions or particles) is that quantity in number argon (Ar), helium (He) etc. are made up of having a mass equal to its atomic or molecular only one atom of that element. But this is not mass in grams. The number of particles (atoms, the case with most of the non-metals. For molecules or ions) present in 1 mole of any example, a molecule of oxygen consists of two substance is fixed, with a value of 6.022 × atoms of oxygen and hence it is known as a 1023. This is an experimentally obtained value. diatomic molecule, O2. If 3 atoms of oxygen This number is called the Avogadro Constant unite into a molecule, instead of the usual 2, we or Avogadro Number (represented by No) get ozone. The number of atoms constituting a  Q.20) Ans: a molecule is known as its atomicity.  Exp: NCERT CLASS 9 18  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912  It was known by 1900 that the atom was not a o While revolving in discrete orbits the simple, indivisible particle but contained at electrons do not radiate energy least one sub-atomic particle – the electron,  In 1932, J. Chadwick discovered another identified by J.J. Thomson. Even before the subatomic particle which had no charge and a electron was identified, E. Goldstein in 1886 mass nearly equal to that of a proton. It was discovered the presence of new radiations in a eventually named as neutron. gas discharge and called them canal rays. These rays were positively charged radiations which  Neutrons are present in the nucleus of all atoms, ultimately led to the discovery of another sub- except hydrogen. In general, a neutron is atomic particle. This sub-atomic particle had a represented as ‘n’. charge, equal in magnitude but opposite in sign to that of the electron. Its mass was  The mass of an atom is therefore given by the approximately 2000 times as that of the sum of the masses of protons and neutrons electron. It was given the name of proton. In present in the nucleus. general, an electron is represented as ‘e– ’ and a proton as ‘p+. Q.23) Ans: C  Since a proton is a positively charged particle Exp: and an electron is a negatively charged particle, the net  The electrons in an atom are arranged in  charge becomes neutral as both the particles different shells/orbits. The electrons present in neutralizes each other. the outermost shell of an atom are known as the valence electrons. Q.21) Ans: B Exp;  From the Bohr-Bury scheme, we also know that the outermost shell of an atom can On the basis of his experiment, Rutherford put accommodate a maximum of 8 electrons. It was forward the nuclear model of an atom, which had observed that the atoms of elements, having a the following features: completely filled outermost shell show little  There is a positively charged centre in an atom chemical activity. In other words, their called the nucleus. Nearly all the mass of an combining capacity or valence is zero. Of these atom resides in the nucleus. inert elements, the helium atom has two electrons in its outermost shell and all other  The electrons revolve around the nucleus in elements have atoms with eight electrons in the well-defined orbits outermost shell.  The size of the nucleus is very small as Q.24) Ans: C compared to the size of the atom. Exp: Q.22) Ans: C  In nature, a number of atoms of some elements Exp: have been identified, which have the same atomic number but different mass numbers. For  In order to overcome the objections raised example, take the case of hydrogen atom, it has against Rutherford’s model of the atom, Neils three atomic species, namely protium (1 1 H), Bohr put forward the following postulates deuterium ( 2 1 H or D) and tritium ( 3 1H or about the model of an atom: T). The atomic number of each one is 1, but the mass number is 1, 2 and 3, respectively. Other o Only certain special orbits known as such examples are (i) carbon, 12 6 C and 14 6 discrete orbits of electrons, are allowed C, (ii) chlorine, 35 17 Cl and 37 17 Cl, etc. On inside the atom. the basis of these examples, isotopes are NCERT CLASS 9 19  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 defined as the atoms of the same element, within it known as cell organelles. Each kind of having the same atomic number but different cell organelle performs a special function, such mass numbers. Therefore, we can say that there as making new material in the cell, clearing up are three isotopes of hydrogen atom, namely the waste material from the cell and so on. A protium, deuterium and tritium. cell is able to live and perform all its functions because of these organelles. These organelles  Many elements consist of a mixture of isotopes. together constitute the basic unit called the cell. Each isotope of an element is a pure substance. It is interesting that all cells are found to have The chemical properties of isotopes are similar the same organelles, no matter what their but their physical properties are different function is or what organism they are found in. Q.25) Ans: d  Plasma membrane is the outermost covering of the cell that separates the contents of the cell Exp: from its external environment. The plasma membrane allows or permits the entry and exit  Since the chemical properties of all the isotopes of some materials in and out of the cell. It also of an element are the same, normally we are not prevents movement of some other materials. concerned about taking a mixture. But some The cell membrane, therefore, is called a isotopes have special properties which find selectively permeable membrane. them useful in various fields. Some of them are: (i) An isotope of uranium is used as a fuel in Q.28) Ans: C nuclear reactors. (ii) An isotope of cobalt is used in the treatment of cancer. (iii) An isotope Exp: of iodine is used in the treatment of goitre.  If the medium surrounding the cell has a higher Q.26) Ans: D water concentration than the cell, meaning that the outside Solution is very dilute, the cell will Exp: gain water by osmosis. Such a is known as a hypotonic Solution. Water molecules are free to  Let us consider two elements — calcium, pass across the cell membrane in both atomic number 20, and argon, atomic number directions, but more water will come into the 18. The number of electrons in these atoms is cell than will leave. The net (overall) result is different, but the mass number of both these that water enters the cell. The cell is likely to elements is 40. swell up.  That is, the total number of nucleons is the same  If the medium has exactly the same water in the atoms of this pair of elements. Atoms of concentration as the cell, there will be no net different elements with different atomic movement of water across the cell membrane. numbers, which have the same mass number, Such a Solution is known as an isotonic are known as isobars. Solution. Water crosses the cell membrane in both directions, but the amount going in is the Q.27) Ans: D same as the amount going out, so there is no overall movement of water. The cell will stay Exp: the same size.  Every multi-cellular organism has come from a  If the medium has a lower concentration of single cell. Cells divide to produce cells of their water than the cell, meaning that it is a very own kind. All cells thus come from pre-existing concentrated Solution, the cell will lose water cells. Each living cell has the capacity to by osmosis. Such a Solution is known as a perform certain basic functions that are hypertonic Solution. characteristic of all living forms. In fact, each such cell has got certain specific components NCERT CLASS 9 20  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 Q.29) Ans: D clean by digesting any foreign material as well as worn-out cell organelles. Foreign materials Exp: entering the cell, such as bacteria or food, as well as old organelles end up in the lysosomes,  The Golgi apparatus consists of stacks of which break them up into small pieces. membrane-bound vesicles whose functions are Lysosomes are able to do this because they as follows: contain powerful digestive enzymes capable of breaking down all organic material. o storage of substances o packaging of substances Q.31) Ans: D o manufacture of substances Exp:  Without the golgi apparatus, the cells will be  A tissue is defined as a cluster of cells which disabled from packing and dispatching are similar in structure and work together to materials that were produced by the cells. The perform a particular function. The use of tissues golgi apparatus is also involved in the in multicellular organisms is to provide formation of cells. Hence, in the absence of structural and mechanical strength as well as to golgi apparatus, cells will not be produced. The allow division of labour.. material synthesised near the ER is packaged and dispatched to various targets inside and  There are noticeable differences between the outside the cell through the Golgi apparatus. Its two that is plant and animal tissues. Plants are functions include the storage, modification and stationary or fixed – they don’t move. Most of packaging of products in vesicles. In some the tissues they have are supportive, which cases, complex sugars may be made from provides them with structural strength. Most of simple sugars in the Golgi apparatus. The Golgi these tissues are dead, since dead cells can apparatus is also involved in the formation of provide mechanical strength as easily as live lysosomes. ones, and need less maintenance. Animals on the other hand move around in search of food, Q.30) Ans: C mates and shelter. They consume more energy Exp: as compared to plants. Most of the tissues they contain are living. Another difference between  Mitochondria are known as the powerhouses of animals and plants is in the pattern of growth. the cell. The energy required for various The growth in plants is limited to certain chemical activities needed for life is released by regions, while this is not so in animals. There mitochondria in the form of ATP (Adenosine are some tissues in plants that divide triphopshate) molecules. ATP is known as the throughout their life. These tissues are localised energy currency of the cell. The body uses in certain regions. Based on the dividing energy stored in ATP for making new chemical capacity of the tissues, various plant tissues can compounds and for mechanical work. be classified as growing or meristematic tissue Mitochondria have two membrane coverings and permanent tissue. Cell growth in animals is instead of just one. The outer membrane is very more uniform. So, there is no such demarcation porous while the inner membrane is deeply of dividing and non-dividing regions in folded. These folds create a large surface area animals. for ATP-generating chemical reactions. Mitochondria are strange organelles in the Q.32) Ans: C sense that they have their own DNA and ribosomes. Therefore, mitochondria are able to Exp: make some of their own proteins.  The growth of plants occurs only in certain  Lysosomes are a kind of waste disposal system specific regions. This is because the dividing of the cell. Lysosomes help to keep the cell tissue, also known as meristematic tissue, is NCERT CLASS 9 21  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 located only at these points. Depending on the Exp: region where they are present, meristematic tissues are classified as apical, lateral and intercalary. New cells produced by meristem  Stomata are the tiny pores present on the outer are initially like those of meristem itself, but as layer of the cells, the epidermis. Stomata bring they grow and mature, their characteristics about the exchange of gases and transpiration. slowly change and they become differentiated as components of other tissues. What happens  Plastids are present only in plant cells. There to the cells formed by meristematic tissue? are two types of plastids – chloroplasts They take up a specific role and lose the ability (coloured plastids) and leucoplasts (white or to divide. As a result, they form a permanent colourless plastids). Plastids containing the tissue. This process of taking up a permanent pigment chlorophyll are known as chloroplasts. shape, size, and a function is called Chloroplasts are important for photosynthesis differentiation. Cells of meristematic tissue in plants. Chloroplasts also contain various differentiate to form different types of yellow or orange pigments in addition to permanent tissue. chlorophyll. Leucoplasts are primarily organelles in which materials such as starch, oils and protein granules are stored. Q.33) Ans: C Q.35) Ans: b Exp: exp:  The covering or protective tissues in the animal body are epithelial tissues. Epithelium covers  Xylem consists of tracheid, vessels, xylem most organs and cavities within the body. It parenchyma, and xylem fibres. The cells have also forms a barrier to keep different body thick walls, and many of them are dead cells. systems separate. The skin, the lining of the Tracheid and vessels are tubular structures. mouth, the lining of blood vessels, lung alveoli This allows them to transport water and and kidney tubules are all made of epithelial minerals vertically. The parenchyma stores tissue. Epithelial tissue cells are tightly packed food and helps in the sideways conduction of and form a continuous sheet. They have only a water. Fibres are mainly supportive in function. small amount of cementing material between Xylem occupies the centre of the vascular them and almost no intercellular spaces. bundle. Water and minerals are transport from Obviously, anything entering or leaving the roots to aerial parts of the plant by Xylem.. body must cross at least one layer of  Phloem is made up of four types of elements: epithelium. As a result, the permeability of the sieve tubes, companion cells, phloem fibres, cells of various epithelia play an important role and the phloem parenchyma. Sieve tubes are in regulating the exchange of materials between tubular cells with perforated walls. Phloem is the body and the external environment and also unlike xylem in that materials can move in both between different parts of the body. directions in it. Phloem transports food from leaves to other parts of the plant. Except for  BLOOD is a connective tissue, the cells of phloem fibres, phloem cells are living cells. connective tissue are loosely spaced and Phloem occurs on the outer side of the vascular embedded in an intercellular matrix. The bundle. Transport of food and nutrients such as matrix may be jelly like, fluid, dense or rigid. sugar and amino acids from leaves to storage The nature of matrix differs in concordance organs and parts of plants done by Phloem. This with the function of the particular connective movement of substances is called translocation. tissue. Q.36) Ans: C Q.34) Ans: C NCERT CLASS 9 22  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 Exp:  The gravitational force between two bodies is directly proportionate to the product of masses  Parthenogenesis can be defined as the of the two objects and inversely proportionate production of an embryo from a female gamete to the square of the distance between them. without any genetic contribution from a male  The electromagnetic force between two bodies gamete, with or without the eventual is directly proportionate to the product of development into an adult. It is distinct from charges of the two objects and inversely asexual reproduction since it involves the proportionate to the square of the distance production of egg cells. between them.  Parthenogenesis is a normal method of  Gravitational force is always attractive while reproduction in many lower organisms, but Electromagnetic force can be both attractive does not lead to viable mammalian offspring. and repulsive. The same charges repel each Parthenogenetic development can proceed by other while opposite charges attract. various routes depending on whether meiosis  The electromagnetic force is not dependent has occurred or has been suppressed, in which upon mass. case the egg develops as result of mitotic divisions. Q.39) Ans: C  Whenever sex is determined by chromosome constitution, parthenogenetic offspring, in the Exp: absence of effective meiosis, all will be, mostly female.  Resonance is a phenomenon in which a vibrating system or external force drives Q.37) Ans: d another system to oscillate with greater amplitude at a specific preferential frequency. Exp: Frequencies at which the response amplitude is a relative maximum are known as the system's resonant frequencies or resonance frequencies. Difference Between Speed and Velocity  A highly trained singer can hit a note that causes glass to shatter due to the phenomenon Velocity Speed of resonance. The natural, or resonant, frequency in the glass, as with all objects, is It refers to the displacement It refers to the determined by its shape and composition. If the of a given object over a time distance moved by singer's voice (or a note from an instrument) interval. an object over a hits the resonant frequency, there will be a time interval. transfer of energy. A full transfer of energy from the voice or musical instrument can It has a specific direction It does not have any overload the glass, causing it to shatter. direction.  Interference of Sound: Two traveling waves that exist in the same medium will interfere Velocity = Speed = distance / with each other. If their amplitudes add, the displacement/time time interference is said to be constructive interference, and destructive interference if Velocity can hold a Speed cannot hold a they are "out of phase" and subtract. negative value negative value.  Reverberation is a result of multiple reflections. A sound wave in an enclosed or semi-enclosed environment will be broken up as it is bounced Q.38) Ans: A back and forth among the reflecting surfaces. Reverberation is, in effect, a multiplicity of Exp: ECHOes whose speed of repetition is too quick NCERT CLASS 9 23  Contact us : [email protected] OnlyIAS Nothing Else Visit : dpp.onlyias.in Contact : +91-7007 931 912 for them to be perceived as separate from one another.  The behavior of a wave (or pulse) upon reaching the end of a medium is referred to as boundary behavior. There are essentially four possible behaviors that a wave could exhibit at a boundary: reflection (the bouncing off of the boundary), diffraction (the bending around the obstacle without crossing over the boundary), transmission (the crossing of the boundary into the new material or obstacle), and refraction (occurs along with transmission and is characterized by the subsequent change in speed and direction). Q.40) Ans: C Pathogens can transmit themselves through all three modes – air, water and soil. Exp: Q.42) Ans: D  The small sized colloidal particles in air can easily scatter a beam of visible light. This Exp: scattering of a beam of light is called the Tyndall effect. Under the Tyndall effect, the  Justification: Even if the air looks clear, it’s longer wavelengths are more transmitted while nearly certain that you’ll inhale tens of millions the shorter wavelengths are more diffusely of solid particles and liquid droplets. These reflected via scattering. The Tyndall effect is ubiquitous specks of matter are known as seen when light- scattering particulate matter is aerosols, and they can be found in the air over dispersed in an otherwise light-transmitting ocesolution, deserts, mountains, forests, ice, medium, when the diameter of an individual and every ecosystem in between. They drift in particle is the range of roughly between 40 and Earth’s atmosphere from the stratosphere to the 900 nm, i.e. somewhat below or near the surface and range in size from a few wavelengths of visible light (400–750 nm). It is nanometers—less than the width of the smallest particularly applicable to colloidal mixtures viruses—to several several tens of and fine suspensions; for example, the Tyndall micrometers—about