CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
A medium has refractive index 1.2. Speed of light in it is approximately:
A. 2.50e+08 m/s
B. 3.00e+08 m/s
C. 3.75e+08 m/s
D. 2.00e+08 m/s
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
A converging lens has focal length 100 cm. Its power is:
A. +1 D
B. +3 D
C. +2 D
D. +0 D
Correct Answer: A
Convert cm to m and use P=1/f.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
A converging lens has focal length 50 cm. Its power is:
A. +3 D
B. +1 D
C. +4 D
D. +2 D
Correct Answer: D
Convert cm to m and use P=1/f.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
A converging lens has focal length 40 cm. Its power is:
A. +2.2 D
B. +2.8 D
C. +3.5 D
D. +2.5 D
Correct Answer: D
Convert cm to m and use P=1/f.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
A converging lens has focal length 25 cm. Its power is:
A. +6 D
B. +4 D
C. +5 D
D. +3 D
Correct Answer: B
Convert cm to m and use P=1/f.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
A converging lens has focal length 20 cm. Its power is:
A. +7 D
B. +5 D
C. +4 D
D. +6 D
Correct Answer: B
Convert cm to m and use P=1/f.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
A converging lens has focal length 10 cm. Its power is:
A. +10 D
B. +11 D
C. +9 D
D. +12 D
Correct Answer: A
Convert cm to m and use P=1/f.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
A converging lens has focal length 5 cm. Its power is:
A. +20 D
B. +19 D
C. +22 D
D. +21 D
Correct Answer: A
Convert cm to m and use P=1/f.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
The visible color with the shortest wavelength is:
A. Orange
B. Violet
C. Red
D. Yellow
Correct Answer: B
Violet has the shortest visible wavelength.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
The visible color with the longest wavelength is:
A. Blue
B. Green
C. Red
D. Violet
Correct Answer: C
Red has the longest visible wavelength.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
Dispersion by a prism occurs because:
A. reflection is absent
B. refractive index varies with wavelength
C. all wavelengths travel identically
D. light has no wave nature
Correct Answer: B
Different wavelengths refract differently.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
Hypermetropia is commonly corrected with a:
A. plane glass only
B. polarizer
C. converging (convex) lens
D. diverging lens
Correct Answer: C
Hypermetropia uses a converging lens.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
Myopia is commonly corrected with a:
A. converging lens
B. plane mirror
C. prism only
D. diverging (concave) lens
Correct Answer: D
Myopia uses a diverging lens.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
Lens power P equals:
A. 1/f with f in metres
B. 1/f²
C. f²
D. f in metres
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
Lens power is measured in:
A. lumens
B. dioptres
C. candelas
D. teslas
Correct Answer: B
Lens power unit is dioptre.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
Total internal reflection requires travel from:
A. lower to higher index
B. air to glass at any angle
C. vacuum to any medium only
D. higher refractive index to lower refractive index
Correct Answer: D
TIR requires higher-to-lower index and angle above critical.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
Light bends toward the normal when entering a medium of:
A. lower index only
B. zero density only
C. higher refractive index from lower refractive index
D. same index
Correct Answer: C
Entering higher n bends toward the normal.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
Refractive index n is:
A. c+v
B. v/c
C. cv
D. c/v
Correct Answer: D
n = c/v.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
A plane mirror forms an image that is:
A. real and inverted
B. real and same size
C. virtual and magnified always
D. virtual, upright and same size
Correct Answer: D
Plane-mirror image is virtual, upright, same size.
CSS - PMS - CCE - PCS - Everyday Science
Light and Optics
The law of reflection states incidence angle equals:
A. reflection angle
B. 90° always
C. refraction angle
D. critical angle
Correct Answer: A
Angles from the normal are equal.