Wave Optics | Physics JEE previous year questions with Solutions

Q 11 :

Two coherent monochromatic light beams of intensities 4 $I$ and 9 $I$ are superimposed. The difference between the maximum and minimum intensities in the resulting interference pattern is x $I$ . The value of x is ________. [2025]

0%

(24)

$I_{\max} = {(\sqrt{I_{1}} + \sqrt{I_{2}})}^{2} = {(\sqrt{4 I} + \sqrt{9 I})}^{2} = 25 I$

$I_{\min} = {(\sqrt{I_{1}} - \sqrt{I_{2}})}^{2} = {(\sqrt{4 I} - \sqrt{9 I})}^{2} = I$

$I_{\max} - I_{\min} = 24 I \Rightarrow x = 24$

Q 12 :

Which of the following are true? [2023]

A. Speed of light in vacuum is dependent on the direction of propagation.
B. Speed of light in a medium is independent of the wavelength of light.
C. The speed of light is independent of the motion of the source.
D. The speed of light in a medium is independent of intensity.

Choose the correct answer from the option given below:

A and C only
B and D only
B and C only
C and D only

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(4)

Speed of light does not depend on the motion of source as well as intensity.

Q 13 :

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R [2023]

Assertion A: The phase difference of two light waves change if they travel through different media having same thickness, but different indices of refraction.

Reason R: The wavelengths of waves are different in different media.

In the light of the above statements, choose the most appropriate answer from the options given below:

Both A and R are correct but R is NOT the correct explanation of A
A is correct but R is not correct
Both A and R are correct and R is the correct explanation of A
A is not correct but R is correct

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(3)

As medium changes, optical path changes.

Also, $\frac{Δ x}{λ} = \frac{Δ ϕ}{2 π}$

Hence phase difference changes.

Q 14 :

The ratio of intensities at two points P and Q on the screen in a Young’s double slit experiment where phase difference between two wave of same amplitude are $π / 3$ and $π / 2$ , respectively are [2023]

1 : 3
3 : 1
3 : 2
2 : 3

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4

(3)

$I_{net} = I_{1} + I_{2} + 2 \sqrt{I_{1} I_{2}} \cos ϕ$

$= I_{0} + I_{0} + 2 I_{0} \cos \frac{π}{3}$

$= 2 I_{0} + 2 I_{0} + \frac{1}{2} = 3 I_{0}$

$I_{net} = I_{0} + I_{0} + 2 I_{0} \cos 90 ° = 2 I_{0}$

$Ratio = \frac{3}{2}$

Q 15 :

In a Young’s double slits experiment, the ratio of amplitude of light coming from slits is 2 : 1. The ratio of the maximum to minimum intensity in the interference pattern is [2023]

9 : 4
9 : 1
2 : 1
25 : 9

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(2)

$Given that \frac{A_{1}}{A_{2}} = \frac{2}{1}$

$\frac{I_{\max}}{I_{\min}} = {(\frac{A_{1} + A_{2}}{A_{1} - A_{2}})}^{2} = \frac{9}{1} = 9 : 1$

Q 16 :

A point source is kept at the center of a spherically enclosed detector. If the volume of the detector increases by 8 times, the intensity will [2026]

decrease by 8 times
increase by 8 times
decrease by 4 times
increase by 64 times

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(3)

Q 17 :

Given below are two statements:

Statement I: A plane wave after passing through a prism remains a plane wave but passing through a small pin hole may become a spherical wave.

Statement II: The curvature of a spherical wave emerging from a slit will increase for increasing slit width.

In the light of the above statements, choose the correct answer from the options given below: [2026]

Statement I is true but Statement II is false
Both Statement I and Statement II are false
Statement I is false but Statement II is true
Both Statement I and Statement II are true

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4

(1)

Topic Question Set

Q 11 :

Two coherent monochromatic light beams of intensities 4 $I$ and 9 $I$ are superimposed. The difference between the maximum and minimum intensities in the resulting interference pattern is x $I$ . The value of x is ________. [2025]

0%

Q 14 :

The ratio of intensities at two points P and Q on the screen in a Young’s double slit experiment where phase difference between two wave of same amplitude are $π / 3$ and $π / 2$ , respectively are [2023]

Q 15 :

In a Young’s double slits experiment, the ratio of amplitude of light coming from slits is 2 : 1. The ratio of the maximum to minimum intensity in the interference pattern is [2023]

Q 16 :

A point source is kept at the center of a spherically enclosed detector. If the volume of the detector increases by 8 times, the intensity will [2026]

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