Science 10 Q2 Reviewer PDF

PROJECT AKADEMYA PREPARED BY: QNHS SUPREME SECONDARY LEARNERS GOVERNMENT GRADE 10 SECOND QUARTER (SCIENCE) LESSON 1. ELECTROMAGNETIC WAVES Electromagnetic waves are waves which can travel through the vacuum of outer space. Electromagnetic waves are fo...

PROJECT AKADEMYA PREPARED BY: QNHS SUPREME SECONDARY LEARNERS GOVERNMENT GRADE 10 SECOND QUARTER (SCIENCE) LESSON 1. ELECTROMAGNETIC WAVES Electromagnetic waves are waves which can travel through the vacuum of outer space. Electromagnetic waves are formed when an electric field couples with a magnetic field. The magnetic and electric fields of electromagnetic waves are perpendicular to each other and to the direction of waves. How do moving charges create magnetic fields? Any moving electric charge is surrounded by an electric field and a magnetic field PRODUCTION OF ELECTROMAGNETIC WAVES When an electric charge vibrates, the electric field around it changes creating a changing magnetic field. The magnetic and electric fields create each other again and again. The electric and magnetic fields vibrate at right angles to the direction the wave travels so it is a transverse wave An EM wave travels in all directions. The figure only shows a wave traveling in one direction. What is the speed of EM waves? All EM waves travel 300,000 km/sec in space. (speed of light-nature's limit!) EM waves usually travel slowest in solids and fastest in gases. Properties of electromagnetic wave 1. All are electromagnetic waves are transverse 2. They do not required any medium to travel through 3. They travel at speed of 3 multiple by 10-8 in vacuum 4. They can all be reflected and refracted. 5. They can all be emitted and absorb by matter. Electromagnetic Spectrum Frequencies is called the electromagnetic spectrum. Different parts interacts with matter in different way As wavelength decreases, frequency increases... The ones humans can see are called visible light, a small part of the whole spectrum. ALSO CALLED AS RMIVUXG RADIO WAVES Radio waves have the longest wavelengths of all the electromagnetic waves. Lowest frequency. Radio waves are often used to transmit data and have been used for all sorts of applications including radio, satellites, radar, and computer networks. USED IN MEDICINE Is used to produce images of soft tissues, fluid, fat and bone. Example: MRI and RFA. Can diagnose many problems Example: can identify tumors Radiofrequency Ablation (RFA) uses heat to destroy cancer cells. MICROWAVES Microwaves are radio waves with wavelengths less than 30 cm and higher frequency & shorter wavelength. Cell phones and satellites use microwaves between 1 cm & 20 cm for communication. Microwaves are useful in communication because they can penetrate clouds, smoke, and light rain. Microwave also in radar that helps to predict the weather. USED IN MEDICINE Hyperthermia therapy is a type of medical treatment. Microwave ablation: used in treatment of liver tumor.  Microwave diathermy: used in pain management. Transurethral microwave: thermotherapy used in treatment of lower urinary tract syndrome. INFRARED WAVES Infrared waves are sometimes classified as "near" infrared or "far" infrared Between microwaves and visible light are infrared waves. Can be detected by heat and used in heat lamp. Higher energy then microwave and lower the visible light. Used daily in remote controls, to read CD-ROMS PRECAUTIONS Strong infrared radiation in certain industry high-heat settings may be hazard to the eyes, resulting in damage or blindness to the user. Since the radiation is invisible, special IR-proof goggles must be worn in su places USES Infrared lamps Digital infrared cameras IMAGING IN MEDICINE Oncology Vascular disorders Respiratory disorders Skeletal neuromuscular disease Surgery Tissue viability VISIBLE LIGHT This is the range of wavelengths from 390 to 700 nm which corresponds to the frequencies 430-790 THz. The portion of the electromagnetic spectrum that human eyes can detect. You see different wavelengths as colors. Violet has shortest Red is the longest Light looks white if all colors are present USED IN MEDICINE Visible light is also used in Scanning laser ophthalmoscope. In Endoscopy/ Keyhole Surgery ULTRA VIOLENT RAYS (UV) Ultraviolet waves have the next shortest wavelength after visible light. EM waves with wavelengths fro about 400 billionths to 10 billionths of a meter. Used in tanning beds and sterilizing equipments. USED IN MEDICINE Have enough energy to enter skin cells Longer wavelengths - UVA Shorter wavelengths - UVB rays Both can cause skin cancer Ultraviolet light is used in treatment of Psoriasis and Vitiligo Pregnancy Abnormalities in the heart and blood vessels  Organs in the pelvis and abdomen Symptoms of pain, swelling and infection X-RAYS High wave energy Used in: Medicines Industry Transportation Too much exposure can damage the living tissue or even cause cancer. USED IN MEDICINE X-rays play an important role in dentistry and orthopedic investigation. They can penetrate soft tissue like skin and muscle. They are used to take X-ray pictures of bones in medicine. GAMMA RAYS Gamma rays the highest energy electromagnetic waves The actually come from radioactive elements or stars Inspection tools in industry USED IN MEDICINE Positron Emission Tomography (PET) is a nuclear medical imaging tool which used gamma rays. Example: Neurological diseases such as Alzheimer's and Multiple Sclerosis Effectiveness of treatments Heart conditions Gamma Knife uses beams of highly focused gamma rays to treat tumors or other abnormalities in the brain. Gamma rays can check how far a cancer has spread and how well treatment is working. HISTORY OF ELECTROMAGNETIC WAVE THEORY William Gilbert (1603): He discovered that Earth was magnetic and theorized that electricity and magnetism are not the same. The unit of magnetic potential, gilbert, was named after him. Charles Augustin de Coulomb (1785): He developed Coulomb's law, which defined the electrostatic force of attraction and repulsion. The Sl unit of charge, coulomb, was named after him. Hans Christian Oersted (1820): He accidentally discovered that electricity could produce magnetism while conducting an experiment in his class. Oersted, a unit of magnetic intensity, was named after him. Joseph Henry (1831): First to discover electromagnetic induction, the production of an electric current across a conductor moving through a magnetic field. The Sl unit for inductance was named after him. Michael Faraday: discovered the "Faraday effect," the first evidence that light and electromagnetism are related. He also discovered electrolysis, the use of electricity to separate matter Wilhelm Eduard Weber (1856): He discovered that the ratio of electrostatic to electromagnetic units equals the value of the speed of light, leading to the conjecture that light is an EM wave. The unit of magnetic flux, weber, was named after him. James Clerk Maxwell (1861): He described how electric charges and currents act as sources of electric and magnetic fields. He formulated four equations - the Maxwell's equations - which summarize the relationship between electricity and magnetism. Heinrich Hertz (1887): He proved the existence of radio waves through his experiments. The Sl unit for frequency was named after him. Albert Einstein (1905): He formulated the concept of photoelectric effect. He was awarded the 1921 Nobel Prize in Physics for the discovery of this law. LESSON 2. EM WAVE CALCULATIONS F.W F=Frequency (f), expressed in (Hz) E=Energy (E), expressed in joules (J) W=Wavelength (λ), expressed in meters (m) Constants speed of an EM wave in vacuum C=3x10^8m/s (^8 means raised to the 8th power) Planck's constant h=6.63×10^-34 J s Sample problems Calculate the wavelength of a wave that has a frequency of 5.24x10^-17 Hz. GIVEN: c=3x10^8m/s λ=? f=5.24×10^-17/s SOLVING: 3x10^8m/s 5.24×10^-17/s (cross the similarities so s will be removed leaving m) = 5.7251908396 =5.73×10^-10m why 5.73 not 5.72? we have to round off it to the nearest number since we need 2 digits in the decimal side and the number beside 2 is 5 we round it of to 3 making it 5.73 instead of 5.72 FINAL ANSWER: λ=5.73×10^-10m LESSON 3. REFLECTION OF LIGHT IN MIRRORS REFLECTION Reflection is the bouncing off of light rays when it hits a surface like a plane mirror. Real Image - formed in front of the mirror and is always upside down relative to the object. It can be projected on a screen placed in front of mirror. Virtual Image - formed behind the mirror and is upright relative to the object and cannot be projected on a screen. The change in direction of a wave when it strikes and rebounds from a surface or the boundary between two media Reflection can be thought of as light "bouncing off" a surface (although this phenomena is much more complex). Regular (specular) reflection - reflection from very smooth (mirror) surfaces. Irregular (diffuse) reflection - reflection from relatively rough surfaces. SPECULAR AND DIFFUSE REFLECTION Images formed by plane mirrors are always virtual, upright, the same size as the object, the same distance behind the mirror as the object is in front of the mirror, and laterally reversed. Laterally reversed means that the left of the object becomes the right of the image, and vice versa. FOR EXAMPLE: Suppose that a girl, with a sitting height of 3ft, is facing 2 ft away from a plane mirror as she puts blush-on on her right cheek. Describe the image formed by each mirror. Explanation: We are given that the girl is 2ft away from the mirror. Recall that images formed by plane mirrors are always virtual, upright, the same size as the object, the same distance behind the mirror as the object is in front of the mirror, and laterally reversed. So the girl will see her image in mirror that is 2ft at its back, meaning it is virtual. It is sitting at at the same size of 3.5ft height and the image will tell us that she is putting blush-on on her left cheek. REFLECTION OF LIGHT IN CURVED MIRRORS KEY TERMS: Center of Curvature, C- the center of which the mirror is part. Its distance from the mirror is radius. known as the Vertex, V- the center of the mirror. Focal Point/Focus, F - the point between the center of the curvature and vertex, Its distance from the mirror is known as the focal length, f. Principal Axis - the point where the reflected rays meet (concave) or where they seem to come from (convex). TYPES OF CURVED MIRRORS Concave mirrors - a concave mirror can produce real or virtual images, depending on the distance between the mirror and the object. The image may also be larger than, the same size as, or smaller than the object. Example: dental mirrors for the dentist to view an enlarged virtual image of the teeth. Convex mirrors - the image formed by a convex mirror is never real because the reflected rays spread out from the mirror. Images formed by convex mirrors are always found between Fand V, virtual, upright, and smaller than the object. Example: side mirror and security mirrors that provide a wider range of view for the driver by making images smaller and closer than they appear. THE FOUR PRINCIPAL RAYS Images formed in a curved mirror can be located and described through ray diagramming. The P-F ray, F-Pray, C-Cray, and the V ray are the 'Four Principal Rays' in curve mirrors. IMAGES FORMED BY CONCAVE MIRRORS AND CONVEX LENS IMAGES FORMED BY A CONVEX MIRROR AND CONCAVE LENS CONCAVE LENS CONVEX LENS USES OF CONCAVE AND CONVEX LENSES goodluck!!