Questions and Answers
Why are electromagnetic waves like ultraviolet rays, X-rays, and gamma rays harmful to living things?
They possess greater energy that they can kill living cells.
Which of the following is a useful application of infrared radiation to humans?
They can show temperature variations of the body.
Which of the following is TRUE about infrared radiation and UV radiation?
Infrared radiation has a longer wavelength than UV radiation.
The following are useful applications of Ultraviolet Radiation EXCEPT
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Which of the following refers to the number of oscillations or wave per unit time and is measured in Hertz (Hz)?
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What wave property can best explain the apparent bending of a pencil when it is dipped into a glass of water?
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When the object is at the center of curvature, the image formed is
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A ray through the center of curvature is reflected at
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Which of the following uses total internal reflection?
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What happens to a light ray as it passes from one medium to another medium?
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A wave with a shorter wavelength must have a higher frequency, and vice versa.
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Which of the following EM waves has the highest energy, greatest frequency, and shortest wavelength?
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What kind of lens should a person with myopia use?
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What image is formed in a concave mirror when the object is at the focal point?
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What is the angle at which a ray of light is reflected from a mirror when it falls on it at an angle of 20° with the surface?
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What is a useful application of infrared radiation to humans?
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Why are electromagnetic waves like ultraviolet rays, X-rays, and gamma rays harmful to living things?
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Which statement is TRUE about infrared radiation and UV radiation?
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Which of the following is NOT a useful application of Ultraviolet Radiation?
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What refers to the number of oscillations or wave per unit time and is measured in Hertz (Hz)?
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What is the term for the maximum displacement of a wave from its rest position?
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Which of the following is a source of electromagnetic waves?
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What kind of lens should a person with myopia use?
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What happens to a light ray as it passes from one medium to another medium?
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Which wave property can best explain the apparent bending of a pencil when it is dipped into a glass of water?
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When the object is between the focal point and mirror, the image formed is:
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What image is formed in a concave mirror when the object is at the focal point?
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Which of the following uses total internal reflection?
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A dentist uses a mirror to enlarge the image of a tooth to have a better view of cavity formations. What type of mirror does the dentist most likely use?
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Which of the following refers to the number of oscillations or waves per unit time and is measured in Hertz (Hz)?
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Study Notes
Electromagnetic Waves
- Electromagnetic waves like ultraviolet rays, X-rays, and gamma rays are harmful to living things due to their high energy and frequency, which can cause damage to cells and tissues.
- Infrared radiation has a useful application in heating and warming, such as in heating pads and night vision devices.
- Infrared radiation has a lower energy and frequency than UV radiation.
Light Waves
- Frequency refers to the number of oscillations or wave per unit time, measured in Hertz (Hz).
- Wavelength and frequency are inversely proportional: a shorter wavelength means a higher frequency, and vice versa.
- Gamma rays have the highest energy, greatest frequency, and shortest wavelength among electromagnetic waves.
Mirrors and Lenses
- A ray through the center of curvature is reflected at the same angle as the incident ray.
- When the object is at the center of curvature, the image formed is real and inverted.
- A concave mirror forms a real and inverted image when the object is at the focal point.
- A person with myopia should use a concave lens to correct their vision.
Reflection and Refraction
- The apparent bending of a pencil when dipped into a glass of water can be explained by the wave property of refraction.
- When a light ray passes from one medium to another, it changes direction due to refraction.
- Total internal reflection is used in fiber optic communication.
Applications of Electromagnetic Waves
- Ultraviolet radiation has useful applications in disinfection, water purification, and cancer treatment.
- Infrared radiation is used in heating pads, night vision devices, and remote controls.
- A dentist uses a concave mirror to enlarge the image of a tooth to have a better view of cavity formations.
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Description
Test your knowledge on electromagnetic waves with this multiple-choice summative test. The test covers topics such as the useful applications of infrared radiation to humans and the harmful effects of electromagnetic waves like ultraviolet rays, X-rays, and gamma rays.
