Fundamentals of Light
1. Which scientist’s experiments confirmed that the speed of light remains constant?
a) James Clark Maxwell
b) Michelson and Morley
c) Miller and Stanley
d) Werner Heisenberg
Answer: b
2. What is the cause behind the golden shine seen in sea shells?
a) Diffraction
b) Dispersion
c) Polarization
d) Reflection
Answer: c
3. When a CD is viewed in sunlight, rainbow-like colors appear due to which phenomenon?
a) Reflection and diffraction
b) Reflection and transmission
c) Diffraction and transmission
d) Refraction, diffraction, and transmission
Answer: d
4. Which phenomenon is not caused by atmospheric refraction?
a) Sun appearing higher than its actual position
b) Sun visible a few minutes before actual sunrise
c) Sun appearing red during sunset
d) Stars twinkling at night
Answer: c
5. In the visible spectrum, red light has more wavelength than green light. Which of the following is correct?
a) Red light is more energetic than green light
b) Red light has higher frequency than green
c) Green light travels faster than red
d) Red light is less energetic than green
Answer: d
Refraction and Reflection
6. The refractive index of a medium is √3. Which statement is correct?
a) sin(i) = √3 × sin(r)
b) i = 2r
c) sin(r) = √3 × sin(i)
d) r = 2i
Answer: a
7. A lens disappears when immersed in a liquid if:
a) Its focal length becomes zero
b) Its focal length becomes infinite
c) Its refractive index is less than the liquid’s
d) Its refractive index equals that of the liquid
Answer: d
8. Total internal reflection occurs when light passes:
a) From diamond to glass
b) From water to glass
c) From air to water
d) From a denser to a rarer medium at an angle greater than the critical angle
Answer: d
9. Which direction of light travel enables total internal reflection?
a) From a rarer to denser medium
b) From a denser to rarer medium
c) From air to water
d) From vacuum to medium
Answer: b
10. When a ray of white light hits a surface and all colors are reflected, the surface appears:
a) Black
b) White
c) Grey
d) Opaque
Answer: b
Optical Instruments and Lenses
11. What type of lens is used in movie projectors?
a) Zoom lens
b) Meniscus lens
c) Concave lens
d) Convex lens
Answer: d
12. If the power of a lens is -2D, what is its focal length?
a) 2 m
b) 1.5 m
c) 1 m
d) -0.5 m
Answer: d
13. How can the magnifying power of a telescope be increased?
a) Decrease the focal length of the eyepiece
b) Increase the diameter of the objective
c) Reduce the focal length of the objective
d) Increase the diameter of the eyepiece
Answer: a
14. The magnifying power of a compound microscope is:
a) m₁ + m₂
b) m₁ / m₂
c) m₁ – m₂
d) m₁ × m₂
Answer: d
15. A girl wants to see an erect image 4 times the size of her face in a concave mirror (radius = 120 cm). How far should she stand?
a) 40 cm
b) 45 cm
c) 50 cm
d) 55 cm
Answer: b
Color, Dispersion, and Perception
16. What color would a blue light in a rocket appear to an observer on Earth if the rocket is receding at 0.2c?
a) Blue
b) Orange
c) Yellow
d) Yellow-orange
Answer: a
17. What will the daytime sky look like to an observer on the Moon?
a) Light yellow
b) Orange
c) Blue
d) Black
Answer: d
18. CMYK is a term related to:
a) Railway signaling
b) Navigation
c) Offset printing
d) Electronic voting machines
Answer: c