CBES Board Class 12 MCQ Quiz Hub

1. For a total internal reflection, which of the following is correct?
Light travels in water only.
Light travels from rarer to denser medium.
Light travels from denser to rarer medium.
Light travels in air only.

2. Mirage is a phenomenon due to
refraction of light
reflection of light
total internal reflection of light
 diffraction of light.

3. A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will
become zero
become infinite
become small, but non-zero
remain unchanged

4. Which of the following forms a virtual and erect image for all positions of the object?
Concave lens
Concave mirror
Convex mirror
Both (1) and (3)

5. Two lenses of focal lengths 20 cm and – 40 cm are held in contact. The image of an object at infinity will be formed by the combination at
10 cm
20 cm
40 cm
infinity

6. Two beams of red and violet color are made to pass separately through a prism (angle of the prism is 60°). In the position of minimum deviation, the angle of refraction will be
30° for both the colors
greater for the violet color
greater for the red color
equal but not 30° for both the colors

7. Which of the following colours of white light deviated most when passes through a prism?
Red light
Violet light
Yellow light
Both (1) and (2)

8. An under-water swimmer cannot see very clearly even in absolutely clear water because of
absorption of light in water
 scattering of light in water
reduction of speed of light in water
change in the focal length of eye lens

9. An astronomical refractive telescope has an objective of focal length 20 m and an eyepiece of focal length 2 cm. Then
the magnification is 1000
the length of the telescope tube is 20.02 m
the image formed of inverted
all of these

10. A rod of length 10 cm lies along the principal axis of a concave mirror of focal length 10 ’em in such a way that its end closer to the pole is 20 cm away from the mirror. The length of the image is
10 cm
15 cm
2.5 cm
5 cm