# Optics Quiz for Fun & Quiz Competition Practice 2

## Results

### #5. A group of parallel rays is called a _______.

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## Optics Quiz Explanation/Physics Quiz

1.(a) Velocity, frequency and wavelength of light don’t change after reflection
from a surface. But the amplitude and intensity of light do change after reflection.
So here the speed of light will remain constant as ‘c’.

1. (b) For a photon, v = c.
So, rest mass of photon, m 0 = m (1 – v 2 /c 2 ) 1/2
= m (1 – c 2 / c 2 ) 1/2
= 0
2. (c) Refractive index depends only upon (i) The color or wavelength of light
(ii) Nature of material of the medium
3. (d) Wave nature can be known when light interacts with itself and all the
properties that are given in the option are the ones in which light interacts
with itself. When light interacts with matter, it indicates its particle nature, e.g.
, photoelectric effect, Raman effect, Compton effect.

## Optics Quiz Explanation/Physics Quiz

1. Light of velocity ‘c’ falls on an area of 4 square metres and gets reflected
back. What will be its speed after reflection?
a. c ()
b. c/4
c. c/2
d. won’t reflect
2. The rest mass of a photon is _.
a. mc 2
b. 0 ()
c. hυ
d. pc
3. Refractive index depends upon __
a. The intensity of light
b. Amplitude
c. Nature of material of the medium ()
d. a & c both
4. Which of the following properties of light indicates its wave nature?
a. Dispersion
b. Polarization
c. Interference
d. All of the above()
5. A group of parallel rays is called a _.
a. Ray light
b. Wave 