Physics · Science General

Optics and Light Properties

2,013 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 separation of substances substances and mixtures formation of mixtures and types of mixtures based on states types of mixtures

When sunlight passes through the window of a classroom, its path is visible. This is due to ________ of light. 

  1. reflection

  2. scattering

  3. saturation

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

Due to Tyndall effect, there occurs scattering of light and the path becomes visible. The dust particles scatter the beam of light.

Multiple choice physics optoelectronic devices resistance and temperature

The principal of LASER action involves

  1. amplification of particular frequency emitted by the system

  2. population inversion

  3. stimulated emission

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Laser action involves all of the following.
(i) Amplification of particular frequency.
(ii) Population of inversion.
(iii) Stimulated emission.

Multiple choice physics optoelectronic devices resistance and temperature

A laser device produces amplification in the

  1. Microwave region

  2. Ultraviolet or visible region

  3. Infrared region

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A laser device produces amplification in the Ultraviolet or visible region of the spectrum. 

Multiple choice physics optoelectronic devices resistance and temperature

LASER is an acronym for light amplification by.

  1. Stimulated energetic radiation

  2. Spontaneous emission of radiation

  3. Stimulated emission of radiation

  4. Spontaneous emission of radio waves
Reveal answer Fill a bubble to check yourself
C 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. The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation".

Multiple choice maths measures and the circle surface area and volume of sphere surface area of a prism surface area of a prism and a pyramid

For a prism, $A = 60^o$, $\mu = \sqrt{\dfrac{7}{3}}$, then the minimum possible angle of incidence, so that the light ray is refracted from the second surface is

  1. $30^o$
  2. $60^o$
  3. $90^o$
  4. $40^o$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For a prism, the condition for refraction at the second surface is that the angle of incidence at the second surface must be less than the critical angle. Using Snell's law and the prism relation r1 + r2 = A, the minimum angle of incidence is found by setting r2 equal to the critical angle.

Multiple choice colon punctuation english

One of the most surprising objects found in his study was a prism; a transparent optical instrument with flat polished surfaces that refract light.

Choose the option that best corrects the underlined word.

  1. NO CHANGE

  2. prism:

  3. prism,

  4. prism ...
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
A colon has several uses, one of them is to link two sentences that are grammatically complete but closely related in thought. 
A semicolon is used between two independent clauses when the coordinating conjunction is omitted.
A comma is used before a coordinating conjunction that joins two independent clauses.
An ellipsis is used to represent a thought trailing off.
Thus, the most suitable answer will be Option B.
Multiple choice physics wave optics interference

A glass wedge of angle $0.01$ radian and $\mu=1.5$ is illuminated by monochromatic light of wavelength $6000\ A$ falling normally on it. At what distance from wedge will $10^{th}$ dark fringe be observed by reflected light ?

  1. $0.1\ mm$
  2. $0.2\ mm$
  3. $0.3\ mm$
  4. $0.4\ mm$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The distance x of the nth dark fringe in a wedge-shaped film is given by x = n * lambda / (2 * mu * theta). Substituting the given values for wavelength, refractive index, and wedge angle gives 0.2 mm.

Multiple choice physics wave optics interference

An isotropic point source emits light. A screen is situated at  a given distance. If the distance between sources and screen is decreased by $2\%$, illuminance will increase by:

  1. $1\%$
  2. $2\%$
  3. $3\%$
  4. $4\%$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
For isotropic point source
$E\propto\dfrac{1}{r^{2}}$

For small change, $\dfrac{\Delta E}{\Delta r}=\dfrac{-2k }{r^{3}}$

$\dfrac{\Delta E}{\Delta r}=-2\dfrac{k}{r^{2}}\dfrac{1}{r}$ or $\dfrac{\Delta E}{\Delta r}=-2\dfrac{E}{r}$

or $\dfrac{\Delta E}{I}=2\left(-\dfrac{\Delta r}{r}\right)\therefore \% \Delta E=2\times 2\%=4\%$

Hence, (d) is correct.

Multiple choice physics oscillations and waves huygen's wave theory refraction of water waves reflection and refraction at plane surfaces theories on light

When the beam of light travels in a medium with lesser velocity than that of in vaccum then the value of wavelength and frequency will respectively

  1. Increase, decrease

  2. Increase, unchanged

  3. Decrease, unchanged

  4. Decrease, decrease
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Energy $=\dfrac{4c}{\lambda }=4\nu $     which is constant.
Here, velocity is decreasing so, to make constant energy $\lambda$ should also decrease and frequency remains constant.

Multiple choice physics oscillations and waves huygen's wave theory refraction of water waves reflection and refraction at plane surfaces theories on light

Consider a light wave that passes from air into a very thick clear glass block that has its opposite internal side mirrored (facing into the glass). The light ray passes into the glass block at an angle greater than $0^{\circ}$ and less than $90^{\circ}$, strikes the mirrored surface and reflects back through the glass into the air.
What happens while the light ray is in the glass block but before it strikes the mirrored surface?

  1. The frequency of the waves increases

  2. The frequency of the waves decreases

  3. The wavelength of the waves decreases

  4. The velocity of the waves decreases

  5. The period of the waves increases
Reveal answer Fill a bubble to check yourself
C,D Correct answer
Explanation

When a light ray enters in a medium of higher refractive index from a lower one, the speed of the wave decreases as $v=\dfrac{c}{\mu}$

Since $\lambda=\dfrac{v}{\nu}$ and the frequency remains unchanged,
$\lambda=\dfrac{\lambda _0}{\mu}$
Hence the wavelength and the velocity of the waves decreases.

Multiple choice physics oscillations and waves huygen's wave theory refraction of water waves reflection and refraction at plane surfaces theories on light

Assertion (A) : Velocity of light is more in rarer medium than in denser medium
Reason (R) : Light waves are longitudinal mechanical waves

  1. Statement A is correct R is wrong

  2. Statement A is correct R is right

  3. Statement A and R both are correct but R is not explaining A

  4. Statement A and R both are correct and R is explaining A
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Velocity of light is more in rarer medium than in denser medium because speed of light in a medium is given by $\dfrac{c}{\mu }$ where, c is speed of light in vacuum and $\mu $ is refractive index of medium. Since denser medium has more $\mu $ than rarer medium, the speed of light is less in medium. Light waves are transverse electromagnetic waves.

Multiple choice physics oscillations and waves huygen's wave theory refraction of water waves reflection and refraction at plane surfaces theories on light


(A) Light is a form of electromagnetic radiation and non-mechanical waves.
(B) Light waves do not require a material as a medium for propagation.

  1. Only A is true.

  2. Only B is true.

  3. Both A and B are true.

  4. Both A and B are false.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Both A and B are true,
Light is a form of electromagnetic radiation and a non-mechanical wave. It does not require a material as a medium for propagation. Hence, it can travel through space.