Q1. What happens to the speed of light when it travels from a rarer medium to a denser medium?
a) Increases
b) Decreases
c) Remains constant
d) Becomes zero
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Correct Answer: b) Decreases
Explanation: When light travels from a rarer medium to a denser medium, its speed decreases due to increased optical density, causing refraction.
Q2. Which of the following is NOT a result of light refraction?
a) Dispersion
b) Reflection
c) Lateral displacement
d) Change in speed
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Correct Answer: b) Reflection
Explanation: Reflection occurs when light bounces off a surface, while refraction involves the bending of light as it passes from one medium to another.
Q3. What is the bending of light as it passes from one transparent medium to another called?
a) Reflection
b) Diffraction
c) Refraction
d) Dispersion
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Correct Answer: c) Refraction
Explanation: Refraction is the bending of light as it passes from one transparent medium to another due to a change in speed.
Q4. In which direction does light bend when it passes from air into water?
a) Away from the normal
b) Towards the normal
c) Parallel to the normal
d) Depends on the angle of incidence
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Correct Answer: b) Towards the normal
Explanation: When light passes from air into water, it bends towards the normal due to the increase in optical density.
Q5. What happens to the angle of refraction when light passes from a denser medium to a rarer medium?
a) Increases
b) Decreases
c) Remains constant
d) Becomes zero
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Correct Answer: a) Increases
Explanation: When light passes from a denser medium to a rarer medium, the angle of refraction increases due to the decrease in optical density.
Q6. What term is used to describe the bending of light around obstacles or through narrow openings?
a) Reflection
b) Diffraction
c) Refraction
d) Interference
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Correct Answer: b) Diffraction
Explanation: Diffraction refers to the bending of light waves around obstacles or through narrow openings, leading to the spreading of light.
Q7. What happens to the wavelength of light when it enters a medium with a higher optical density?
a) Increases
b) Decreases
c) Remains constant
d) Becomes zero
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Correct Answer: b) Decreases
Explanation: When light enters a medium with a higher optical density, its wavelength decreases, leading to a change in speed and direction.
Q8. Which of the following phenomena is caused by the dispersion of light during refraction?
a) Mirage
b) Rainbow
c) Polarization
d) Total internal reflection
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Correct Answer: b) Rainbow
Explanation: Rainbow formation is caused by the dispersion of sunlight into its component colors during refraction and reflection inside water droplets.
Q9. What is the name of the angle formed between the incident ray and the normal line at the point of incidence?
a) Angle of incidence
b) Angle of refraction
c) Angle of reflection
d) Critical angle
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Correct Answer: a) Angle of incidence
Explanation: The angle of incidence is the angle formed between the incident ray and the normal line at the point of incidence on a surface.
Q10. What term is used to describe the phenomenon when light does not pass through a boundary and is instead reflected back into the original medium?
a) Refraction
b) Diffraction
c) Reflection
d) Dispersion
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Correct Answer: c) Reflection
Explanation: Reflection occurs when light does not pass through a boundary and is instead reflected back into the original medium, obeying the law of reflection.