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 light and shadow substances which allow light to pass through and those which do not transparent, opaque and translucent objects shadows

Air is not visible because it :

  1. is a nearly perfectly transparent substance

  2. neither absorbs nor reflects light

  3. transmits whole of light

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

The absorptive capacity of air is very low, hence it transmits most of the light rays passing through it.

Multiple choice physics light and shadow substances which allow light to pass through and those which do not transparent, opaque and translucent objects shadows

Air is not visible because it

  1. is nearly perfectly transparent substance

  2. neither absorbs nor reflects light

  3. transmits whole of light

  4. all the above are correct
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Air is not visible because it is transparent medium. As from definition of transparent medium, their reflectance and emitance is zero , hence it transmits all the light.

Multiple choice physics light and shadow substances which allow light to pass through and those which do not transparent, opaque and translucent objects shadows

A body which allows almost all the light to pass through it and does not reflect any light is a-

  1. transparent body

  2. opaque body

  3. translucent body

  4. polished surface
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Objects which allow the light to pass through them completely without any obstruction or reflection are called $ \bf{transparent} $ objects.

Objects which do not allow the light to pass through them are called $\bf{opaque} $ objects.

Objects which allow the light to pass through them partially are called $ \bf{translucent} $ objects.

Polished surfaces are good reflectors of light and do not allow light to pass through it. 

Hence, the correct answer is OPTION A.

Multiple choice physics light and shadow substances which allow light to pass through and those which do not transparent, opaque and translucent objects shadows

A medium which partially allows the light rays to pass through it is called -

  1. transparent

  2. opaque

  3. non-luminous

  4. translucent
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Objects or medium which allow the light to pass through them completely without any obstruction are called $ \bf{transparent} $ objects or medium.

Objects or medium which do not allow the light to pass through them are called $\bf{opaque} $ objects or medium.

Objects which do not emit light on their own are called  $ \bf{non-luminous} $ objects.

Objects or medium which allow the light to pass through them partially are called $ \bf{translucent} $ objects or medium.

Hence, the correct answer is OPTION D. 

Multiple choice physics light and shadow substances which allow light to pass through and those which do not transparent, opaque and translucent objects shadows

Glass allows light to pass through it because it is -

  1. transparent

  2. opaque

  3. luminous

  4. non-luminous
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Objects which allow the light to pass through them completely without any obstruction are called $ \bf{transparent} $ objects.

Objects which do not allow the light to pass through them are called $\bf{opaque} $ objects.

Objects that give out or emit light of their own are called as $ \bf{luminous} $ objects.

Objects which do not emit light on their own are called $ \bf{non-luminous}$ objects.

Thus, glass allows light to pass through it because it is transparent and doesn't block any light. 

Hence, the correct answer is OPTION A.  

Multiple choice physics light and shadow substances which allow light to pass through and those which do not transparent, opaque and translucent objects shadows

Cellophane paper is an example of -

  1. an opaque object

  2. a translucent object

  3. a transparent object

  4. a luminous object
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Objects which do not allow the light to pass through them are called $\bf{opaque} $ objects.

Objects which allow the light to pass through them partially are called $ \bf{translucent} $ objects.

Objects which allow the light to pass through them completely without any obstruction are called $ \bf{transparent} $ objects.

Objects that give out or emit light of their own are called as $ \bf{luminous} $ objects.

Since, cellophane paper allows light to pass through it completely, it is a transparent object. Also, it doesn't emit any light. 

Hence, the correct answer is OPTION C.  
Multiple choice physics light and shadow substances which allow light to pass through and those which do not transparent, opaque and translucent objects shadows

An object is transparent if you can see through it clearly.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A transparent substance is defined as the substance through which all light incident on it normally can pass through it.And hence , it can be seen clearly through a transparent substance.


Given statement is $True$.

Multiple choice physics superposition of waves-1: interference and beats interference of sound waves superposition and interference of sound waves properties of sound waves

Which of the following is true?

  1. Both the light and sound waves exhibit interference

  2. Light waves exhibit interference

  3. Sound waves exhibit interference

  4. Neither sound waves nor light waves exhibit interference
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Interference is a fundamental property of all wave phenomena, including both light (electromagnetic waves) and sound (mechanical waves).

Multiple choice physics wave optics polarization of light polarisation of light polarisation

An unpolarised light of intensity $32  \mathrm{W} / \mathrm{m}^{2}  $ passes through three polarisers, such that the transmission axis of last polarizer is perpendicular with the first. If the intensity of emergent light is $3  \mathrm{Wh}  $ Im $ ^{2} $ then the angle between the transmission axes of the first two polarisers is:

  1. $ 30^{\circ} $
  2. $ 19^{\circ} $
  3. $ 45^{\circ} $
  4. $ 90^{\circ} $
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Using Malus's Law, the intensity after the first polarizer is I1 = I0/2 = 16. After the second, I2 = 16*cos^2(theta). After the third (perpendicular to the first), I3 = I2*cos^2(90-theta) = 16*cos^2(theta)sin^2(theta) = 16(sin(2*theta)/2)^2 = 4*sin^2(2*theta). Setting 4*sin^2(2*theta) = 3 gives sin^2(2*theta) = 3/4, so sin(2*theta) = sqrt(3)/2, meaning 2*theta = 60 degrees, or theta = 30 degrees.

Multiple choice physics oscillations and waves polarization of light polarisation of light polarisation

Two polaroids are oriented with their transmision axes making angle of $30^{\circ}$ with each other. The fraction of indicent unpolarised light is transmitted.

  1. $37\%$
  2. $37.5\%$
  3. $3.36\%$
  4. $36.5\%$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The intensity after the first polarizer is I0/2. The intensity after the second polarizer is I = (I0/2)cos^2(30). Since cos(30) = sqrt(3)/2, cos^2(30) = 3/4. Thus, I = (I0/2)(3/4) = 3/8 * I0 = 0.375 * I0, which is 37.5%.

Multiple choice physics oscillations and waves polarization of light polarisation of light polarisation

The axes of the polarizer and analyzer are inclined to each other at an angle of $60^{o}$. If the amplitude of polarized light emerging through the analyzer is $A$, the amplitude of unpolarized light incident on the polarizer is

  1. $A/2$
  2. $A$
  3. $2A$
  4. $2\sqrt{2}\ A$.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let I0 be the initial intensity. After the polarizer, intensity is I1 = I0/2. After the analyzer, I2 = I1*cos^2(60) = (I0/2)*(1/4) = I0/8. Since intensity is proportional to the square of amplitude (I = k*A^2), A_emergent^2 = (A_incident^2)/8. Thus, A_incident = A*sqrt(8) = 2*sqrt(2)*A.

Multiple choice physics oscillations and waves polarization of light polarisation of light polarisation

Two polorides are placed having their transmission axis at an angle of $45^0$. If unpolarised light is incident on first polorid acting as polarizer then, calculate intensity of emergent light from second polariser:-

  1. $I _0$
  2. $\frac{I _0}{4}$
  3. $\frac{I _0}{2}$
  4. $2I _0$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Intensity after the first polarizer is I1 = I0/2. Applying Malus's Law for the second polarizer at 45 degrees: I2 = I1*cos^2(45) = (I0/2)*(1/2) = I0/4.