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 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 colour of light emitted by a LED depends on

  1. Its reverse bias

  2. The amount of forward current

  3. Its forward bias

  4. Type of semiconductor material
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The color of an LED is a function of the material used to make the junction. There are two main flavors used in visible light LED junctions:

 
Indium gallium nitride (InGaN) is used to make up the blue, white, true green, and UV types. 

Aluminum gallium indium phosphide (AlGaInP or AlInGaP) is used to make the red, yellow, and orange types. 

The type of material used also has an effect on the rated forward voltage of the LED.

Multiple choice physics optoelectronic devices resistance and temperature

The colour of light emitted by an LED depends on

  1. Its reverse bias

  2. The amount of forward current

  3. Its forward bias

  4. Type of semiconductor material
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The colour of LED depends on the band gap of the semiconductor material used. When there is an electron transition, the light corresponding to that energy is emitted.

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

LED glows even when a ______ electric current passes through it. Fill in the blank.

  1. weak

  2. strong

  3. can't predicted

  4. none of the above

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

Principle of LED is the reverse of principle of photo electric effect.

hence even when a weak electric current passes through a circuit respective number of some light photons releases from the LED.
Hence LED glows but with low intensity.

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
A Correct answer
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.