Physics · Science General

Optics and Light Properties

2,019 Questions

Optics and light properties focus on the behavior of light, including reflection, refraction, dispersion, and polarization. This topic also covers the wave nature of light, illumination, and the functioning of optical instruments like microscopes. Questions on these concepts are common in general science sections of SSC, Railways, and State exams.

Reflection and mirrorsRefraction and mediumsLight wave theoriesPolarization and intensity

Optics and Light Properties Questions

Multiple choice

Which one of the following phenomena cannot be attributed to the refraction of high?

  1. Twinkling of stars

  2. Mirage

  3. Rainbow

  4. Red Shift
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Red shift is caused by the Doppler effect or the expansion of the universe, where the wavelength of light is stretched. In contrast, the twinkling of stars, mirages, and rainbows are all phenomena caused by the refraction of light as it passes through different media. The term 'high' in the question is a typo for 'light'.

Multiple choice

Total internal reflection of light can occur only when light passes

  1. from a denser to a rarer medium

  2. from a rarer to a denser medium

  3. from one medium to another of equal refractive index

  4. from one medium to another of equal absorption
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Total internal reflection of light can occur only when light passes from a denser to a rarer medium. 

Multiple choice

Which of the following statements about light rays is incorrect?

  1. Light always propagates along a straight line.

  2. Two light rays do not disturb each other upon intersection.

  3. An object and its image are interchangeable.

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Light propagates almost in a straight line. It bends at some positions due to certain obstacles like buildings, different objects and rigid bodies present in the universe, so option 1 is incorrect.

Multiple choice

One cannot see through fog because

  1. fog absorbs light

  2. light is scattered by the droplets in the fog

  3. light suffers total reflection in the droplets in the fog

  4. the refractive index of fog is infinity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

One cannot see through fog because light is scattered by the droplets in the fog. 

Multiple choice

The ratio of refractive index of red light to that of blue light is

  1. less than unity

  2. equal to unity

  3. greater than unity

  4. less as well as greater than unity, depending upon the experimental arrangements
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

It is less than unity because refractive index is directly proportional to wavelength of light. Wavelength of light from red to blue decreases, so the refractive index increases. So, the ratio of refractive index of red light to that of blue light is less than unity.

Multiple choice

The refractive index of glass with respect to water is 9/8. It implies that

  1. the speed of light respectively is 9 times and 8 times slower in glass and water with respect to vacuum

  2. the speed of light in glass is 9/8 times faster than that in water

  3. <font size="2" face="Arial">the speed of light in water is 9/8 times faster than that in glass</font>

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The speed of light in water is 9/8 times faster than that in glass.

Multiple choice

If a diver in a swimming pool wants to signal his distress to a person lying on the edge of the pool by flashing his waterproof flashlight, then

  1. he must direct the beam vertically upwards

  2. he has to direct the beam horizontally

  3. he has to direct the beam at an angle to the vertical, which is slightly less than the critical angle of incidence for total internal reflection

  4. he has to direct the beam at an angle to the vertical, which is slightly less than the critical angle
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

He has to direct the beam at an angle to the vertical, which is slightly less than the critical angle of incidence for total internal reflection.

Multiple choice

A rainbow is formed due to ______________ through a water droplet.

  1. reflection and dispersion of light

  2. refraction, reflection and dispersion of light

  3. only dispersion of light

  4. only refraction of light

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A rainbow is a meteorological phenomenon caused by reflection, refraction, and dispersion of light in water droplets, resulting in a spectrum of light appearing in the sky.

Multiple choice

What type of light does a laser produce?

  1. X-rays

  2. Microwaves

  3. Gamma rays

  4. Coherent light

  5. White light
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. A laser differs from other sources of light in that it emits light coherently.