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 physics effects of light scattering of light and its applications some natural phenomena of light natural phenomena explained by scattering

After scattering, the light moves in:

  1. the same direction as the original light ray.

  2. opposite to the original direction of the light ray.

  3. all directions.

  4. the direction of the shortest path.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In scattering,  light wave is absorbed and re-emitted in all directions without a change in the wavelength of the light ray.

Multiple choice physics effects of light scattering of light and its applications some natural phenomena of light natural phenomena explained by scattering

As the thickness of the atmosphere increases colour of scattered light is found in ________ order.

  1. Blue, violet, yellow, red

  2. Violet, blue, yellow, red

  3. Red, yellow, blue, violet

  4. Violet, blue, red, yellow
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The short-wavelength blue and violet are scattered by molecules in the air much more than other colors of the spectrum because of which blue and violet light reaches our eyes from all directions.

As thickness of atmosphere increase,  more molecules are available to scatter the violet and blue light away from our eyes. If the path is long enough, all of the blue and violet light scatters out of our line of sight.  and he other colors orange, red continue on their way to your eyes.
The sky often appears red because larger particles of dust, pollution, and water vapor in the atmosphere reflect and scatter more of the reds and yellows.
Option D 

Multiple choice physics effects of light scattering of light and its applications some natural phenomena of light natural phenomena explained by scattering

The clear sky appears blue because:

  1. blue light gets absorbed in the atmosphere.

  2. ultraviolet radiations are absorbed in the atmosphere.

  3. violet and blue lights get scattered more than lights of all other colours by the atmosphere.

  4. light of all other colours is scattered more than the violet and blue colour lights by the atmosphere.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The scattering of light depends on the size of the dust particles and the wavelength of the light. The amount of scattering is inversely proportional to the fourth power of wavelength.
Since, violet and blue lights get scattered more than lights of all other colours by the atmosphere the sky appears blue.

Multiple choice physics effects of light scattering of light and its applications some natural phenomena of light natural phenomena explained by scattering

Which of the following phenomena contributes significantly to the reddish appearance of the sun at sunrise or sunset?

  1. Dispersion of light

  2. Scattering of light

  3. Total internal reflection of light

  4. Reflection of light from the earth
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

We see red colour of the sun at sunrise or sunset as the sun at horizon and light rays need to travel a greater distance. In the process of scattering, violet, blue and green rays in the original sunlight are removed and the transmitted beam has yellow and red dominant.

Multiple choice physics effects of light scattering of light and its applications some natural phenomena of light natural phenomena explained by scattering

Tyndall effect is applicable when?

  1. The diameter of the dispersed particle is not much smaller than the wavelength of the light used

  2. The diameter of the dispersed particles is much smaller than the wavelength of the light used

  3. The refractive indices of the dispersed phase and the dispersion medium must be same

  4. The refractive indices of the dispersed phase and the dispersion medium must differ greatly in magnitude
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Tyndall effect occurs when light is scattered by particles in a colloid or fine suspension. This phenomenon is most pronounced when the size of the particles is comparable to the wavelength of the incident light.

Multiple choice physics effects of light scattering of light and its applications some natural phenomena of light natural phenomena explained by scattering

Which of the following statements is correctregarding the propagation of light of differentcolours of white light in air?

  1. Red light moves fastest

  2. Blue light moves faster than green light

  3. All the colours of the white light move with the same speed in empty space

  4. Yellow light moves with the mean speed as that of the red and the violet light
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In a vacuum or empty space, all electromagnetic waves, including all colors of visible light, travel at the same constant speed (the speed of light, c).

Multiple choice physics effects of light scattering of light and its applications some natural phenomena of light natural phenomena explained by scattering

Which of the following phenomena cannot be explained by scattering of light ?

  1. Blue colour of sky

  2. Colour of clouds

  3. Tyndall effect

  4. Formation of rainbow
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Answer is D.

The rainbow is caused by light from the sun (or moon) interacting with raindrops falling from the air. These raindrops are mostly round. A ray of light entering such a droplet is bent (refracted) and decomposed into all possible colors (wavelengths) which the white light consists of. The ray then reflects internally in the droplet, and emerges roughly into the direction it came from when it entered the drop. Since the rays of the different colors all exit at slightly different directions, we see a color band in the sky.
The colors are produced by a phenomenon called dispersion. Dispersion causes white light, which consists of all possible colors to break up into all components, when the light travels from one medium (e.g. air) to another (e.g. water). The different colors of light have all slightly different directions, so if we look in a certain direction in the sky we can see the spectrum.

Multiple choice physics effects of light scattering of light and its applications some natural phenomena of light natural phenomena explained by scattering

When is the direction of scattered light independent of the wavelength?

  1. Medium of travel is not air.

  2. Particles involved in scattering have size smaller than the wavelength of the incident light wave.

  3. Particles involved in scattering have size larger than the wavelength of the incident light wave.

  4. Particles scattering the light wave are not neutral in charge.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Particles smaller than the wavelength of light scatters the light in all directions. In visible spectrum, they scatter violet the most and red the least. However, when the particles are larger than the wavelength of light, then the scattering of all wavelengths occur to same extent.

Multiple choice physics effects of light scattering of light and its applications some natural phenomena of light natural phenomena explained by scattering

The process of re-emission of absorbed light in all directions with different intensities by the atom or molecule is called ____________.

  1. Scattering of light

  2. Dispersion of light

  3. Reflection of light

  4. Refraction of light
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$Scattering$ is the process of absorbed light in all possible directions with different intensities and frequency by an atom or a molecule.


Answer-(A)