# Optics Quiz for Fun & Quiz Competition Practice 1

## Results Related Spread the love Related Spread the love #1. If a plane mirror is turned through 400, how much will the reflected ray turn through? (In degrees) 120 120 50 50 80 80 20 20 #2. What will be the transverse magnification of a mirror if the lengths of object and image are, L0 = -6 cm, Li = 216 cm? 36 cm 36 cm +6 cm +6 cm – 60 cm – 60 cm +36 cm +36 cm #3. A concave mirror is held in water. What would be the change in the focal length of the mirror f will be halved f will be halved f will change, as per the medium f will change, as per the medium f will be doubled f will be doubled f won’t change f won’t change #4. The power of a plane mirror is ________. Infinity Infinity Zero Zero 1 D 1 D None of the above None of the above #5. If a ray is incident on a plane mirror at an angle of π/6, then it suffers a deviation of _______. π/6 π/6 π/3 π/3 2π/3 2π/3 π/2 π/2 finish

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Physics Quiz Explanation is given below

1.(c) If a plane mirror turns through a certain angle, the reflected ray turns through double the original angle. So here the plane mirror turns through 400, hence the reflected ray gets deviated, 2 x 400 = 800

2.(b) Transverse magnification is also called lateral magnification, which is equal to m.

Here m2 = -Li/L0

So, m2 = – 216/ -6 = 36

Or, m = 6

3.(b) focal length won’t change because f doesn’t depend upon the external medium in which mirror is held.

4.(b) The power of a plane mirror is zero because,

For a plane mirror, f = ꚙ

Power, P = 1/f = 1/ ꚙ

= 0

5.(b) If a ray is incident on a plane mirror at a angle of incidence i , then it suffers a deviation of (π-2i).

Here i = π/6

So deviation, π-2i = π-(2x π/6) = 2π/3.

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1. If a plane mirror is turned through 400, how much will the reflected ray turn through? (In degrees)

a. 120

b. 50

c. 80 ()

d. 20

2. What will be the transverse magnification of a mirror if the lengths of object and image are, L0 = -6 cm, Li = 216 cm?

a. -36 cm

b. +6 cm ()

c. – 60 cm

d. +36 cm

3. A concave mirror is held in water. What would be the change in the focal length of the mirror?

a. f will be halved

b. f won’t change ()

c. f will be doubled

d. f will change, as per the medium

4. The power of a plane mirror is ________.

a. Infinity

b. Zero ()

c. 1 D

d. None of the above

5. If a ray is incident on a plane mirror at an angle of π/6, then it suffers a deviation of _______.

a. π/6

b. 2π/3 ()

c.  π/3

d.  π/2