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 chemistry nature of matter heterogenous mixture - colloidal solution and its properties suspensions and colloids mixtures

A liquid is found to scatter a beam of light but leaves no residue when passed through the filter paper. The liquid can be described as :

  1. a suspension

  2. oil

  3. a colloidal sol

  4. a true solution
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A liquid is found to scatter a beam of light (due to Tyndall effect) but leaves no residue when passed through the filter paper (as the size of the particles is smaller than the pores of the filter paper).
The liquid can be described as a colloidal sol.

Multiple choice physics electromagnetic waves and communication system maxwell's equations the nature of light introduction to electromagnetic waves

This question has statement-1 and statement-2. Of the four choices given after the Statements, choose the one that best describes the two statements.
Statement 1: Short wave transmission is achieved due to the total internal reflection of the e-m wave from an appropriate height in the ionosphere.
Statement 2: Refractive index of a plasma is independent of the frequency of e-m waves.

  1. Statement 1 is true, Statement 2 false.

  2. Statement 1 is false, Statement 2 is true

  3. Statement 1 is true, Statement 2 is true but statement 2 is not the correct of statement 1.

  4. Statement 1 is true, statement 2 is true and statement 2 is the correct explanation of statement 1.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Statement 1 is true because the ionosphere reflects radio waves, enabling long-distance communication. Statement 2 is also true because the refractive index of plasma depends on the electron density and the frequency of the wave, but the statement as written is a common physics textbook fact that the refractive index varies with frequency, making the statement 'independent' false. However, given the options, the question implies both are true but unrelated.

Multiple choice physics observing space: telescopes maxwell's equations the nature of light introduction to electromagnetic waves

The electromagnetic radiations used for taking photographs of objects in dark.

  1. $X$-rays

  2. Infra-red rays
  3. $\gamma$ rays
  4. $UV$ rays
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Answer is B.

Infrared (IR) is invisible radiant energy, electromagnetic radiation with longer wavelengths than those of visible light, extending from the nominal red edge of the visible spectrum at 700 nano-meters to 1 mm. 
Infrared is used in night vision equipment when there is insufficient visible light to see. Night vision devices operate through a process involving the conversion of visible light photons into electrons that are then amplified by a chemical and electrical process and then converted back into visible light. Infrared light sources can be used to enhance the available visible light for conversion by night vision devices, increasing in-the-dark visibility without actually using a visible light source.

Multiple choice physics observing space: telescopes maxwell's equations the nature of light introduction to electromagnetic waves

Light appears to travel in a straight line, because.

  1. Its wavelength is very small

  2. Its velocity is large

  3. It is not absorbed by surroundings

  4. It is reflected by surroundings
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Light appears to travel in a straight line because diffraction (or deviation from the path) is least in light. Diffraction is least because -of small wavelength of light. So small wave length of light causes the light to travel almost in straight line.

Multiple choice physics observing space: telescopes maxwell's equations the nature of light introduction to electromagnetic waves

Reflection of a light wave at a fixed point results in a phase difference between incident and reflected wave of

  1. $\dfrac{3\pi}{2}$
  2. $2 \pi $ rad
  3. $\pi$ rad
  4. $\dfrac{\pi}{2}$ rad
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Reflection of light wave at fixed point result in phase difference b/w incident and reflected ray of $\pi$. The wave gets inverted. Inversion behavior is noticed when medium is connected to dense medium.

Multiple choice evs life in water aquatic plant adaptations pollination through water aquatic adaptation extreme adaptations

In an aquatic ecosystem, the depth to which light penetrates is called

  1. aphotic

  2. photic

  3. euphotic

  4. nonphotic
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The photic zone is the depth in an aquatic ecosystem where sunlight penetrates and photosynthesis is possible. Aphotic zones receive no light, euphotic is a specific subtype of photic zone, and 'nonphotic' is not standard terminology.

Multiple choice evs - ii our earth and our solar system solar system and sun planets and stars introduction to solar system planets sunita's experience in space space exploration

Venus appears very bright because it reflects about ....... percent of the light which it receives from the Sun.

  1. 50

  2. 60

  3. 75

  4. 100
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

First of all venus is very close to earth so very less amount of light gets scattered by atmosphere particles and second thing is it reflects $75\%$ of the light coming from sun.

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 statement is correct?

  1. At sunset or sunrise, the suns rays have to pass through a small distance in the atmosphere.

  2. At sunset or sunrise the suns rays have to pass through a larger distance in the atmosphere.
  3. Rayleigh scattering which is proportional to $(l/\lambda)^2$

  4. Most of the blue and other shorter wavelengths are not removed by scattering.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

At sunset or sunrise the suns rays have to pass through a larger distance in the atmosphere and most of the blue and other shorter wavelengths are remove by scattering.

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

An astronaut in a spaceship the sky appears black due to:

  1. Absence of atmosphere in his neighbourhood

  2. Light from the sky is absorbed by the medium surrounding him

  3. The fact at the height, sky radiations are only in the infra-red and the ultraviolet region

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

To an astronaut it will appear as black.On earth we see the blue sky due to presence of atmosphere. Atmosphere refracts light ray coming from the sun and we see the colour of sky.In space, due to the absence of the atmosphere the light rays do not refract and reach the astronomer's eyes therefore it appears black.

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

One cannot see through fog because .......... .

  1. Fog absorbs light

  2. Refractive index of fog is unity

  3. Light suffers total internal reflection at the droplets in fog

  4. Light is scattered by the droplets in fog
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Answer is D.
We cannot see through fog because of scattering.
Atoms and molecules in the air, including anything carried in the air like dust or smoke, will scatter light. Water droplets, as they are present in fog, also scatter light. The light falling on an object and reflected to a viewer can be scattered to heck and back before it gets to the place where it can be 'seen' by an observer. So the observer just sees a 'whiteout' instead of being able to make out anything beyond a few meters or so.

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

Sodium lamps are used in foggy conditions because:

  1. yellow light is scattered less by the fog particles

  2. yellow light is scattered more by' the fog particles

  3. yellow light is unaffected during its passage through the fog

  4. Wavelength of yellow light is the mean of the visible part of the spectrum
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The higher the wavelength the lesser the scattering. Yellow light has higher wavelength so it is least likely to be scattered among all colours in the visible region (except red & orange). So this light is visible from long distance even when there is foggy weather.

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

The phenomenon of scattering of light by fine particles is called _____ :

  1. Snell's law

  2. Dispersion effect

  3. Law of refraction

  4. Tyndall effect
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The earths atmosphere is a heterogeneous mixture of minute particles like smoke, tiny water droplets, suspended particles of dust and molecules of air. When a beam of light strikes such fine particles, the path of the beam becomes visible. This phenomenon of scattering of light by the colloidal particles is called Tyndall effect.