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Assignments Chapter 1: mains of electricity multiple choice questions 1. The diagram at the right shows a. A lamp b. A resistor c. A capacitor d. A circuit breaker 3. The energy released from hot rocks and water underground is called A. Wave energy B....

Assignments Chapter 1: mains of electricity multiple choice questions 1. The diagram at the right shows a. A lamp b. A resistor c. A capacitor d. A circuit breaker 3. The energy released from hot rocks and water underground is called A. Wave energy B. Wind energy C. Geothermal energy D. Hydro electric energy 4. An electric kettle shown below is a device converts a. Electrical energy to heat energy b. Kinetic energy to potential energy c. Heat energy to electrical energy d. Wind energy to thermal energy Prepared by Mohamoud Yusuf Mohamoud said (timo-jilic)1  4. The diagram shows four types of power station. Which type of power station uses chemical energy to generate electricity? 6. Hydroelectric power produces electricity using: A. Wind B. Sunlight C. Moving water 7. The diagram shows a hydroelectric system. i. What are the main energy changes take place? ii. chemical energy---> kinetic energy ---> electrical energy iii. electrical energy ---> gravitational energy ---> kinetic energy iv. gravitational energy ---> kinetic energy --->electrical energy v. kinetic energy ---> electrical energy ---> gravitational energy 8. Which of the following electrical appliances will use the greatest amount of electrical energy? An appliance with a rating of: A. 1,000 watts used for 3 hours C. 800 watts used for 4 hours B. 1,500 watts used for 3 hours D. 500 watts used for 5 hours Prepared by Mohamoud Yusuf Mohamoud said (timo-jilic)2 9. Which of the following is a renewable source of energy? a. Coal B. Hydroelectric power c) Natural gas d) nuclear 10. Of the following choices, which best describes or defines biomass a. Massive living things b. Inorganic matter that can be converted to fuel c. Petroleum D. Organic matter that can be converted to fuel 11. Which energy source is directly from the Sun? a. biomass C) hydroelectric d) solar e) natural gas 12. Which of the following is non-renewable energy source? a. Hydroelectric B. Wind C. Solar D. Oil 13. Which of the following is NOT a fossil fuel? a. Uranium B. Coal C. Natural gas D. oil 14. What is the source of the energy converted by a hydro-electric power station? A. Hot rocks B. falling water C. Oil D. waves 15. Energy from the sun is known as : b Solar energy B. hydroelectric energy C. wind energy 16. The figure shows a three- pin plug in a domestic wiring system. Which correctly illustrate the correct wire connection 17. All of the following are renewable energy sources except a. Biomass energy b. coal c. Hydroelectric energy d. solar energy 18. Which of the following does not emit greenhouse gases when used for energy? a. Coal b. ethanol c. Hydroelectric energy d. petroleum 19. The main purpose of the earth wire is Prepared by Mohamoud Yusuf Mohamoud said (timo-jilic)3  a. To complete then electric circuit c. To reduce heating effect b. To prevent explosion d. To prevent electric shock 20. You have the choices of a 5A, 10A, and 13A fuses. Which one would you fit to a 1000W hair drier with 240V mains supply? a. 3A fuse b. 13A fuse c. 5A fuse d. 10A fuse A. Part two: Structured Questions 1. The diagram below shows electricity generated from a Hydro-power station. a. State two advantages of hydroelectric power? 1)............... 2)................ b. State at least two disadvantages of hydropower to wildlife animals 1)............... 2)................ c. State the form of energy that water has at the reservoir.................................. d. What is the taking place when energy changes water from the reservoir falls down........................... e. What is the function of the turbines.................. f. Which part converts kinetic energy into electrical energy......... Prepared by Mohamoud Yusuf Mohamoud said (timo-jilic)4 g. Write the energy changes in hydroelectric power.................................. 2) Name four of the main sources of mains electricity?............................................................................... 3) What is the function of heating element?.......................... 4) The diagram below shows three pin plug a) Label the indicated parts with letters A, B, C, D, E and F from the given list. Fuse (A), Cable (B), Cable Grip(C), Neutral (D), Earth(E), Live (F) b) what is the function of each of the following parts: i. The live wire........................... ii. The neutral wire.......................... iii. The fuse............................ iv. The earth wire.......................... v. The plastic covers?......................... 5) What are the colors of the three wires and tell their position Wire Live wire Neutral wire Earth wire Color Position Prepared by Mohamoud Yusuf Mohamoud said (timo-jilic)5  6) The diagrams below show four electrical appliances a) Which two devices transform energy at same rate?....... and...... b) The kettle is used in 2hrs, how much energy does it transfer?..................................................................................................................... c) If the radiator is switched on in 2hrs, it transfers 2kwh of energy. So what will be the cost of this energy if the cost rate is $0.5 per kWh?...................................................................................................................... d) What kind of energy do these devices transform to each other?....................................... 7. The pie chart shows how a country's electricity demands are met using different energy sources. a) What percentage of electricity is generated? i. From non-renewable _____________ ii. From geothermal source. ___________ iii. From a source which produces radioactive waste ________ iv. Using kinetic energy directly ____________ b) What percentage of electricity from the pie chart can cause I. Global warming........................ II. Acid rain........................ c) State two advantages of generating electricity from Prepared by Mohamoud Yusuf Mohamoud said (timo-jilic)6  I. Wind................................................................ II. Nuclear............................................................ 8. Calculate electricity bills in the table below. Present meter reading previous meter reading Unit used Cost per unit $ Cost $ 2586 2520 0.8 6312 6212 0.8 8431 8221 0.8 9. Using the word box below, fill the correct word to the empty spaces. Solar energy , renewable energy, wind energy, hydroelectric energy, fossil fuels, potential energy, nuclear energy, kinetic energy 1) These energy sources cause global warming because they produce CO 2 ___________ 2) Wind mills change _____________________from the moving wind to electrical energy 3) Solar, wind, and hydroelectric are examples of sources that can be used again and again. These are called by _____________________________ 4) The energy which is stored in the nucleus of certain atoms is ____________The energy due to the falling water from the dam ________________________ 5) The kind of energy which stored in the water in the dam or the lake is ______________ 6) The energy that we receive from the sun is ___________________________________ Prepared by Mohamoud Yusuf Mohamoud said (timo-jilic)7 Chapter2: Electric Magnetic Waves PART ONE: multiple choice questions 1. Electromagnetic Waves which plants use photosynthesis in order to make their own food is called a. Gamma rays c. X-rays b. Visible light d. Radio waves 2. VHF stands for a. Very high frequency c. Volume high frequency b. Very high-volume d. Vertical horizontal volume 3. Ahmed and Ali see this diagram. It shows some parts of the electromagnetic spectrum. The radiation in part P is: Radio wave Micro wave Infrared p ultraviolet a. visible light b) gamma rays c) X-rays d) ultrasound 4............ are used at airports to detect aero planes. A. Infrared C. ultraviolet B. microwave D. x-ray 5. In a vacuum, all The type of electromagnetic waves have the same : A. Wavelength B. Frequency C. Speed D) Amplitude 6. Which electromagnetic waves have the longest wavelengths? a) Radio waves B) Microwaves C) Infrared rays d) Visible light 7. Electromagnetic radiation comes in different forms. Which pair do not appear next to one another in the electromagnetic spectrum? a. microwaves, ultraviolet C. visible light, infrared b. X-rays, ultraviolet D. radio waves, microwaves 8. Which component of the electromagnetic spectrum is used for television transmission from satellites? a. Microwaves b. radio waves c. ultra-violet d. X-rays Prepared by Mohamoud Yusuf Mohamoud said (timo-jilic)8  9. Where are gamma-rays used? a. fluorescent tubes b). killing cancerous cells c) pre-natal scanning 10. Which statement is correct? a. Gamma rays have a longer wavelength than ultra-violet waves. b. Infra-red waves have a lower frequency than radio waves. c. Microwaves have a longer wavelength than visible light. d. X-rays have a higher speed in air than visible light. 11. Which wave property has the same value for all electromagnetic waves travelling in air? a. Amplitude b. frequency c. speed d. wavelength 12. The electromagnetic waves consist two Fields those propagate perpendicular to each other as shown below diagram! The Fields are: - a) Electric and Gravity c) Contact and Non-contact b) Electric and Magnetic d) All above Part two : structural questions 1) Match the electromagnetic radiation in column A and some uses of electromagnetic radiation in column B Column A Number Column B 1. Gamma rays A. In a remote control for a TV 2. X-rays B. To communicate with satellites 3. Ultraviolet rays C. To sterilize surgical instrument 4. Infrared rays D. In sunbeds to give a suntan 5. Microwaves E. To obtain shadow pictures of bones 2) State three properties that Electromagnetic waves have in common. a. ----------------------------------------------------------------------------------------------- b. ----------------------------------------------------------------------------------------------- Prepared by Mohamoud Yusuf Mohamoud said (timo-jilic)9  c. ----------------------------------------------------------------------------------------------- The wavelengths of waves in the electromagnetic spectrum range from approximately 10-13 m for gamma to 103 m for radio waves as shown in Figure below. a. Name the radiation in the regions A and B A................ B................ b. Name the type of wave that has the lowest frequency ____________________ c. Name the type of wave that has the greatest energy_____________________ d. Used to take photographs of the bones of the broken leg? ________________ e. Which is emitted by the by the nucleus of radioactive material__________ f. Used for sight and photosynthesis? ______________________ g. Used for phone communications? _______________________ 4) Data is sent between two stations A and B using radio waves which travel to and from the satellite. Station A and B are both 300,000km each from the satellite. The speed of radio waves is 300 000 000m/s a) Calculate the time taken for data to travel from A to B. time = distance / speed............................................................ a) Which station shows ground transmitter?.............. b) Which station shows ground receiver.............. c) AM stands for.......................... Prepared by Mohamoud Yusuf Mohamoud said (timo-jilic)10  d) UHF stands for........................... e) Calculate frequency of that wave........................................................................................ Chapter 1: VECTORS ONE PART ONE: multiple choice questions 1. which team wins the competition? A. Team 1 B. Team 2 C. Team 1 and Team 2 2. The Resultant Force is: A. 354N C. 250N B. 104N D. 604N 3. The direction of Team 2 is A. Left side B. Right side C. No direction D. Down 4. Splitting a vector into horizontal and vertical is called ……………. a) Parallel vectors B) Resolving vectors C) parallelogram vector D) combining 5. Which of the following is vector quantity a) Distance B) Speed C) Displacement D) Temperature 6. When there is no force acting on a body it said to be ……………. A) Resultant force B) vertical force C) horizontal force D) equilibrium 7. 80km to left and 55km to right the resultant displacement is ………….. a) 135km to left B) 25km to left C) 25km to right D) 25km to north 1) Calculate horizontal and vertical components Part two : structural questions 2) calculate resultant displacement of a) 60km left and 40km right............................ b) 70m west , 140m north 5km of south......................... Calculate the resultant force and its direction of each of the following figures Prepared by Mohamoud Yusuf Mohamoud said (timo-jilic)11  3) Two teams are pulling a rope against each other as shown in the figure below.. a) Calculate the resultant force................................ b) which team is wins the competition?.......................... CHAPTER THREE: NUCLEAR PHYSICS 1. Which of the following particles is emitted during alpha decay? a) Proton b) Neutron c) Alpha particle d) Beta particle 2. What is the atomic number of an element with 9 protons? a) 8 b) 9 c) 18 d) 19 4. What is the main reason some elements are radioactive? a) Excess neutrons or protons b) High mass number c) Low atomic number d) Equal protons and neutrons 5. The process in which a neutron is converted into a proton and an electron is called: a) Alpha decay b) Gamma decay c) Beta decay d) Fission Prepared by Mohamoud Yusuf Mohamoud said (timo-jilic)12 Section B: Structured Questions 6. Answer the following. a) Define radioactivity. b) State two ways in which radioactive decay occurs. --------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------ 7. Use the element below to answer the questions : An atom has 6 protons and 7 neutrons. a) What is the atomic number of this atom? __________________________ b) What is the mass number of this atom? ___________________________ c) Write the notation for this atom._________________________________ 8. Differentiate between isotopes and isobar --------------------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------------------- A: SHORT ANSWER QUESTIONS 1. Which type of radiation has: a) Negative charges------------------------------------------------------ b) Positive charge------------------------------------------------------- c) The speed of light---------------------------------------------------- d) Stopped by a sheet of paper-------------------------------------- e) Lowest ionization effect------------------------------------------- 2. Which type of radiation is: a) Not affected by a magnetic field. b) Made up of 2 protons and 2 neutrons. c) An electron released from the nucleus of an unstable atom. 3. Write nuclear equations to show the radioactive decay of: a) Technetium (99-Tc) by decay of beta particles __________________ b) Thorium (232-Th) by decay of alpha particles___________________ SECTION B: 4. Define the following terms: a) Radioactivity------------------------------------------------------------------------------------------------- ------------------------- b) Atomic number-------------------------------------------------------------------------------------------- c) Mass number--------------------------------------------------------------------------------------------- *5. Differentiate between the following:* a) Isotopes and isobars. b) Alpha particles and beta particles. Prepared by Mohamoud Yusuf Mohamoud said (timo-jilic)13