Medicine and Allied Sciences
Engineering and Architecture
Management and Business Administration
Law
Animation and Design
Media, Mass Communication and Journalism
Finance & Accounts
Computer Application and IT
Pharmacy
Hospitality and Tourism
Competition
School
Study Abroad
Arts, Commerce & Sciences
Learn
Online Courses and Certifications

How Many Days Left for NEET 2025? - Countdown NEET 2025

Home
NEET
Study Material
Interference Of Light - Condition And Types MCQ - Practice Questions with Answers

Interference Of Light - Condition And Types MCQ - Practice Questions with Answers

Edited By admin | Updated on Sep 25, 2023 25:23 PM | #NEET

Syllabus
Application Process
Exam Pattern
Admit Card
Preparation Tips
Result
Cutoff
Counselling Process
Answer Key
Mock Test
Exam Analysis
Question Paper
College Predictor
Eligibility Criteria
Dates
College Predictor
Rank Predictor
Accepting Colleges
Study Material

Quick Facts

Interference of light waves- 1, Interference of light waves- 2 is considered one of the most asked concept.
29 Questions around this concept.

Solve by difficulty

Two waves $\mathrm{y}_{1}=\mathrm{A}_{1} \sin \left(\omega \mathrm{t}-\beta_{1}\right)$ and $\mathrm{y}_{2}=\mathrm{A}_{2} \sin \left(\omega \mathrm{t}-\beta_{2}\right)$ superimpose to form a resultant wave. The amplitude of this resultant wave is given by

A

$\mathrm{A_{1}+A_{2}}$

Correct Answer

Wrong Answer

B

$\mathrm{\left|A_{1}-A_{2}\right|}$

Correct Answer

Wrong Answer

C

$\mathrm{\sqrt{A_{1}^{2}+A_{2}^{2}+2 A_{1} A_{2} \cos \left(\beta_{1}-\beta_{2}\right)}}$

Correct Answer

Wrong Answer

D

$\mathrm{\sqrt{A_{1}^{2}+A_{2}^{2}-2 A_{1} A_{2} \cos \left(\beta_{1}-\beta_{2}\right)}}$

Correct Answer

Wrong Answer

The time of exposure for a photographic print is 10 seconds when a lamp of 50 cd is placed at 1 m from it. Then another lamp of luminous intensity I is used and is kept at 2 m from it. If the time of exposure now is 20 s, the value of I (in cd) is

A

25

Correct Answer

Wrong Answer

B

50

Correct Answer

Wrong Answer

C

200

Correct Answer

Wrong Answer

D

20

Correct Answer

Wrong Answer

A parallel beam of white light falls on a thin film whose refractive index is 1.33. If the angle of incidence is $52^{\circ}$ , then the thickness of the film for the reflected light to be coloured yellow $(\lambda=6000 \AA)$ most intensively must be

A

$14(2 \mathrm{n}+1) \mu \mathrm{m}$

Correct Answer

Wrong Answer

B

$1.4(2 \mathrm{n}+1) \mu \mathrm{m}$

Correct Answer

Wrong Answer

C

$0.14(2 \mathrm{n}+1) \mu \mathrm{m}$

Correct Answer

Wrong Answer

D

$142(2 n+1) \mu m$

Correct Answer

Wrong Answer

NEET 2024: Cutoff (OBC, SC, ST & General Category)

NEET 2024 Admission Guidance: Personalised | Study Abroad

NEET 2025: Syllabus | Most Scoring concepts | NEET PYQ's (2015-24)

NEET PYQ's & Solutions: Physics | Chemistry | Biology

The interference pattern is obtained with two coherent light sources of intensity ratio n. In the interference pattern, the ratio $\frac{{I_{\max } - I_{\min } }} {{I_{\max } + I_{\min } }}$ will be :

A

$\frac{{\sqrt n }} {{n + 1}}$

Correct Answer

Wrong Answer

B

$\frac{{2\sqrt n }} {{n + 1}}$

Correct Answer

Wrong Answer

C

$\frac{{\sqrt n }} {{\left( {n + 1} \right)^2 }}$

Correct Answer

Wrong Answer

D

$\frac{{2\sqrt n }} {{\left( {n + 1} \right)^2 }}$

Correct Answer

Wrong Answer

In the Young's double-slit experiment, the intensity of light at a point on the screen where the path difference is $\lambda$ is K, ( $\lambda$ being the wave length of light used). The intensity at a point where the path difference is $\frac{\lambda }{4}$ , will be:

A

$K$

Correct Answer

Wrong Answer

B

$\frac{K}{4}$

Correct Answer

Wrong Answer

C

$\frac{K}{2}$

Correct Answer

Wrong Answer

D

$Zero$

Correct Answer

Wrong Answer

In Young's double slit experiment, one of the slits is wider than the other, so that the amplitude of the light from one slit is double of that from the other slit. If I_m be the maximum intensity, the resultant intensity I when they interfere at phase difference $\phi$ is given by :

A

$\frac{I_{m}}{9}\left ( 4+5\cos \phi \right )$

Correct Answer

Wrong Answer

B

$\frac{I_{m}}{3}\left ( 1+2\cos^{2}\frac{\phi }{2} \right )$

Correct Answer

Wrong Answer

C

$\frac{I_{m}}{5}\left ( 1+4\cos^{2}\frac{\phi }{2} \right )$

Correct Answer

Wrong Answer

D

$\frac{I_{m}}{9}\left ( 1+8\cos^{2}\frac{\phi }{2} \right )$

Correct Answer

Wrong Answer

A ray of light of intensity $I$ is incident on a parallel glass slab at point $A$ as shown in the diagram. It undergoes partial reflection and refraction. At each reflection, $25 \%$ of incident energy is reflected. The rays $A B$ and $A^{\prime} B^{\prime}$ undergo interference. The ratio of $I_{\max }$ and $I_{\min }$ is :

A

49 : 1

Correct Answer

Wrong Answer

B

7 : 1

Correct Answer

Wrong Answer

C

4 : 1

Correct Answer

Wrong Answer

D

8 : 1

Correct Answer

Wrong Answer

Pearson | PTE

Register now for PTE & Unlock 20% OFF : Use promo code: 'C360SPL20'. Valid till 31st DEC'24! Trusted by 3,500+ universities globally

Two beams of light having intensities I and 4 I interfere to produce a fringe pattern on the screen. The phase difference between the beams is $\frac{\pi}{2}$ at point a and $\pi$ at point B. The difference of intensities at A and B is

A

3 I

Correct Answer

Wrong Answer

B

4 I

Correct Answer

Wrong Answer

C

5 I

Correct Answer

Wrong Answer

D

6 I

Correct Answer

Wrong Answer

The intensity of the central bright fringe due to interference of two identical coherent monochromatic sources is I. If one of the sources is switched off, then the intensity of the central bright fringe becomes

A

$\frac{1}{2}$

Correct Answer

Wrong Answer

B

$\frac{1}{3}$

Correct Answer

Wrong Answer

C

$\frac{1}{4}$

Correct Answer

Wrong Answer

D

$1$

Correct Answer

Wrong Answer

Most Scoring concepts for NEET

This ebook serves as a valuable study guide for NEET exams, specifically designed to assist students in light of recent changes and the removal of certain topics from the NEET exam.

In an interference pattern by two identical slits, the intensity of central maxima is $\mathrm{I}$ . If one slit is closed, the intensity of central maxima changes to $\mathrm{I}_{0}$ . Then $\mathrm{I}$ and $\mathrm{I}_{0}$ are related by

A

$\mathrm{I=I_{0}}$

Correct Answer

Wrong Answer

B

$\mathrm{I}=2 \mathrm{I}_{0}$

Correct Answer

Wrong Answer

C

$I=3 \mathrm{I}_{0}$

Correct Answer

Wrong Answer

D

$\mathrm{I=4 I_{0}}$

Correct Answer

Wrong Answer

Concepts Covered - 2

Interference of light waves- 1

In order to observe interference in light waves, the following conditions must be met:

The sources must be coherent.
The source should be monochromatic (that is, of a single wavelength).

Coherent sources-

Two sources are said to be coherent if they produce waves of the same frequency with a constant phase difference.

The relation between Phase difference $(\Delta \phi )$ and Path difference $(\Delta x )$

Phase difference $(\Delta \phi )$ :

The difference between the phases of two waves at a point is called phase difference.

$\text { i.e. if } y_{1}=a_{1} \sin \omega t \text { and } y_{2}=a_{2} \sin (\omega t+\phi) \text { so phase difference }=\phi$

Path difference $(\Delta x )$ :

The difference in path lengths of two waves meeting at a point is called path difference between the waves at that point.

And The relation between Phase difference $(\Delta \phi )$ and Path difference $(\Delta x )$ is given as

$\Delta \phi =\frac{2\pi }{\lambda }\Delta x=k\Delta x$

where $\lambda =wavelength \ of \ waves$

Interference of light waves- 2

Principle of Super Position-

According to the principle of Super Position of waves, when two or more waves meet at a point, then the resultant wave has a displacement (y) which is the algebraic sum of the displacements ( $y_1 \ \ and \ \ y_2$ ) of each wave.

i.e $y=y_1+y_2$

consider two waves with the equations as

$\begin{array}{l}{y_{1}=A_{1} \sin (k x-w t)} \\ {y_{2}=A_{2} \sin (k x-w t+\phi)}\end{array}$

where $\phi$ is the phase difference between waves $y_1 \ \ and \ \ y_2$ .

And According to the principle of Super Position of waves

$\begin{aligned} y=& y_{1}+y_{2}=A_{1} \sin (k x-w t)+A_{2} \sin (k x-w t+\phi) \\ &=A_{1} \sin (k x-w t)+A_{2}[\sin (k x-w t) \cos \phi+\sin \phi \cos (k x-\omega t)] \\ \Rightarrow y &=\sin (k x-w t)\left[A_{1}+A_{2} \cos \phi\right]+A_{2} \sin \phi \cos (k x-w t) \dots (1) \end{aligned}$

Now let

$Acos\theta =A_{1}+A_{2} \cos \phi \\ and \ \ Asin\theta=A_{2} sin \phi$

Putting this in equation (1) we get

$y=A \sin (k x-\omega t) \cos \theta+A \sin \theta \cos (k x-\omega t)$

thus we get the equation of the resultant wave as

$y=A \sin (k x-\omega t+\theta)$

where A=Resultant amplitude of two waves

and $A= \sqrt{{A_{1}}^{2}+{A_{2}}^{2}+2A_{1}A_{2}\cos \phi}$

and $\theta=\tan^{-1} (\frac{A_{2} \sin \phi }{A_{1}+A_{2} \cos \phi})$

where

$A_{1}=$ the amplitude of wave 1

$A_{2}=$ the amplitude of wave 2

$\begin{array}{c} \ \ A_{\max }={a_{1}+a_{2}} \ \ and \ \ A_{\min }={a_{1}-a_{2}}\end{array}$

Resultant Intensity of two waves (I)-

Using $I \ \ \alpha \ \ A^2$

we get $I= I_{1}+I_{2}+2\sqrt{I_{1}I_{2}}\cos \phi$

where

$I_{1}=$ The intensity of wave 1

$I_{2}=$ The intensity of wave 2

$\begin{aligned} \ \ I_{\max } &=I_{1}+I_{2}+2 \sqrt{I_{1} I_{2}} \Rightarrow I_{\max } &=(\sqrt{I_{1}}+\sqrt{I_{2}})^{2} \end{aligned}$
$\begin{array}{c}{I_{\min }=I_{1}+I_{2}-2 \sqrt{I_{1} I_{2}}} \Rightarrow {I_{\min }=(\sqrt{I_{1}}-\sqrt{I_{2}})^{2}} \end{array}$
For identical source-

$I_{1}=I_{2}=I_{0} \Rightarrow I=I_{0}+I_{0}+2 \sqrt{I_{0} I_{0}} \cos \phi=4 I_{0} \cos ^{2} \frac{\phi}{2}$

$\text { Average intensity : } I_{a v}=\frac{I_{\max }+I_{\min }}{2}=I_{1}+I_{2}$
The ratio of maximum and minimum intensities

$\frac{I_{\max }}{I_{\min }}=\left(\frac{\sqrt{I_{1}}+\sqrt{I_{2}}}{\sqrt{I_{1}}-\sqrt{I_{2}}}\right)^{2}=\left(\frac{\sqrt{I_{1} / I_{2}}+1}{\sqrt{I_{1} / I_{2}}-1}\right)^2=\left(\frac{a_{1}+a_{2}}{a_{1}-a_{2}}\right)^{2}=\left(\frac{a_{1} / a_{2}+1}{a_{1} / a_{2}-1}\right)^{2}$

or

$\sqrt{\frac{I_{1}}{I_{2}}}=\frac{a_{1}}{a_{2}}=\left(\frac{\sqrt{\frac{I_{\max }}{I_{\min }}}+1}{\sqrt{\frac{I_{\max }}{I_{\min }}-1}}\right)$

Interference of Light-

It is of the following two types.

1. Constructive interference-

When the waves meet a point with the same phase, constructive interference is obtained at that point.

i.e we will see bright fringe/spot.

The phase difference between the waves at the point of observation is $\phi=0^{\circ} \text { or } 2 n \pi$
Path difference between the waves at the point of observation is $\Delta x=n \lambda(i . e . \text { even multiple of } \lambda / 2)$
The resultant amplitude at the point of observation will be maximum

$\begin{array}{c} i.e \ \ A_{\max }={a_{1}+a_{2}} \\ {\text { If } a_{1}=a_{2}=a_{0} \Rightarrow A_{\max }=2 a_{0}}\end{array}$

Resultant intensity at the point of observation will be maximum

$\begin{aligned} \ \ i.e \ \ I_{\max } &=I_{1}+I_{2}+2 \sqrt{I_{1} I_{2}} \\ I_{\max } &=(\sqrt{I_{1}}+\sqrt{I_{2}})^{2} \\ \text { If } \quad I_{1} &=I_{2}=I_{0} \Rightarrow I_{\max }=4 I_{0} \end{aligned}$

2. Destructive interference-

When the waves meet a point with the opposite phase, Destructive interference is obtained at that point.

i.e we will see dark fringe/spot.

The phase difference between the waves at the point of observation is

$\begin{array}{l}{\phi=180^{\circ} \text { or }(2 n-1) \pi ; n=1,2, \ldots} \\ {\text { or }(2 n+1) \pi ; n=0,1,2 \ldots .}\end{array}$

Path difference between the waves at the point of observation is $\Delta x=(2 n-1) \frac{\lambda}{2}(\text { i.e. odd multiple of } \lambda / 2)$
The resultant amplitude at the point of observation will be maximum

$\begin{array}{c} i.e \ \ A_{\min }={a_{1}-a_{2}} \\ {\text { If } a_{1}=a_{2} \Rightarrow A_{\min }=0}\end{array}$

Resultant intensity at the point of observation will be maximum

$\begin{array}{c}{I_{\min }=I_{1}+I_{2}-2 \sqrt{I_{1} I_{2}}} \\ {I_{\min }=(\sqrt{I_{1}}-\sqrt{I_{2}})^{2}} \\ {\text { If } I_{1}=I_{2}=I_{0} \Rightarrow I_{\min }=0}\end{array}$

Study it with Videos

Interference of light waves- 1

Interference of light waves- 2

Study other Related Concepts

Interference Of Light - Condition And Types Current Topic

Laws Of Reflection

Reflection On A Plane Mirror

Object And Image Velocity In Plane Mirror

Spherical Mirrors

Image Formation By Spherical Mirrors

Spherical Mirror Formula And Magnification

Refraction Of Light

Real Depth And Apparent Depth

Total Internal Reflection

Refraction Of Light Through Glass Slab

"Stay in the loop. Receive exam news, study resources, and expert advice!"

Get Answer to all your questions

NEET Articles

NEET Qualifying Marks 2024 Reduced (Out)- Qualifying Score for NEET UG

Dec 26, 2024

How Many Marks are Required in NEET for Government Colleges?

Dec 26, 2024

Assam NEET Counselling 2024: Stray Vacancy Round Choice Filling (Closed), Seat Allotment

Dec 26, 2024

NEET 2025 Registration Date (Out Soon) by NTA- Check Latest Updates Here

Dec 26, 2024

NIRF Ranking 2024 Medical Colleges (Out)- Top 50 Medical Colleges in India

Dec 24, 2024

NEET 2025 Exam Language Options by NTA- Check Here

Dec 24, 2024

NTA NEET 2026 Syllabus PDF: Official Download NEET Exam Syllabus

Dec 24, 2024

Deleted Topics in NEET 2025 by NTA: Reduced Chapters & Topics List

Dec 24, 2024

Quick Facts
Practice Questions
Concept Covered
Concept Video

Begin a career in Medical and Allied Sciences. Admissions Open for

NEET College Predictor

Know possible Govt/Private MBBS/BDS Colleges based on your NEET rank

NEET Companion

Register for Careers360 NEET Counseling & Admission Guidance Service.

TOEFL ® Registrations 2024

Accepted by more than 11,000 universities in over 150 countries worldwide

Manav Rachna-MRIIRS Allied Health Sciences Admissions 2025

Admissions open for Bachelor of Physiotherapy, B.Sc Nutrition & Dietetics ,B.Sc Food Science & Technology

View All Application Forms

News and Notifications

Bihar NEET UG 2024 stray vacancy seat allotment result tomorrow; confirm admission till December 29

December 26, 2024 - 09:11 AM IST

Bihar NEET UG 2024 special stray vacancy round 3 choice-filling deadline today; allotment on December 27

December 25, 2024 - 08:05 AM IST

Bombay HC grants admission to MBBS aspirant in Maharashtra college through supernumerary seat

December 24, 2024 - 07:58 PM IST

Bihar NEET UG 2024 Counselling: Special stray vacancy round 3 schedule out; allotment on December 27

December 23, 2024 - 06:07 PM IST

NEET 2025 Physics: 5 tips to tackle the ‘most challenging’ subject; key chapters to focus on

December 23, 2024 - 02:08 PM IST

MCC NEET UG 2024 special stray vacancy round 3 choice filing begins today; lock preferences at mcc.nic.in

December 23, 2024 - 07:57 AM IST

MCC NEET UG 2024 Counselling: Special stray vacancy round 3 schedule out; choice filling begins tomorrow

December 22, 2024 - 01:50 PM IST

Explore on Careers360

NEET

NEET Application Form

NEET Admit card

NEET Syllabus

NEET Answer Key

NEET Cutoff

NEET Result

NEET Exam Dates

NEET Counselling

RPVT

RPVT Application Form

RPVT Admit Card

RPVT Answer Key

RPVT Result

RPVT Seats

RPVT Syllabus

AIIMS Nursing

AIIMS Nursing Application Form

AIIMS Nursing Admit Card

AIIMS Nursing Result

Indian Army BSc Nursing

Indian Army BSc Nursing Application Form

Indian Army BSc Nursing Admit Card

Indian Army BSc Nursing Model Question Paper

Indian Army BSc Nursing Result

By Degree

Top M.B.B.S. Colleges in India

Top B.Sc. Colleges in India

Top B.D.S. Colleges in India

By Branch

Top Pathology Colleges in India

Top Gynaecology and Obstetrics Colleges in India

Top General Medicine and Surgery Colleges in India

Top General Nursing and Midwifery Colleges in India

By Exam

Medical Colleges in India Accepting NEET

By City

Top Medical Colleges in Bangalore

Top Medical Colleges in Chennai

Top Medical Colleges in Kolkata

Top Medical Colleges in Pune

Top Medical Colleges in Mumbai

Top Medical Colleges in New Delhi

Top Medical Colleges in Hyderabad

Top Medical Colleges in Ahmedabad

By State

Top Medical Colleges in Maharashtra

Top Medical Colleges in Karnataka

Top Medical Colleges in Tamilnadu

Top Medical Colleges in Punjab

Top Medical Colleges in Uttar Pradesh

Top Medical Colleges in Rajasthan

Top Medical Colleges in Madhya Pradesh

Top Medical Colleges in Gujarat

Top Medical Colleges in West Bengal

Download Careers360 App

All this at the convenience of your phone

Regular Exam Updates
Best College Recommendations
College & Rank predictors
Detailed Books and Sample Papers
Question and Answers

Scan and download the app

OR

About
Hiring
Magazine
News
Contact
Blogs

Medical Colleges in India
Private Medical Colleges in India
Government Medical Colleges in India
Government Medical Colleges in Uttar Pradesh
Medical Colleges in Tamil Nadu
Medical Colleges in Maharashtra
Medical Colleges in Karnataka
Medical Colleges in Kerala
Medical Colleges in Bihar
Medical Colleges in West Bengal
Medical Colleges in Haryana
AIIMS Delhi
CMC Vellore

NEET 2025
NEET MDS Exam
NEET PG 2024
FMGE 2024
INI CET 2025 January Session
AIAPGET 2024
NEET SS 2024
DNB PDCET 2024
AIIMS Bsc Nursing Exam
AIAPGET 2024

NEET Rank Predictor
NEET PG Rank Predictor
NEET College Predictor
NEET PG College Predictor
DNB CET College Predictor
DNB PDCET College Predictor
NEET MDS College Predictor
Medical E-books
Medical Sample Papers
NEET E-Books
Download NEET Sample Papers

NEET Exam
NEET Counselling 2024
NEET PG Counselling 2024
NEET Cut off
NEET Study Material 2025
NEET Online Preparation
Popular Medical Branches
QnA - Get answers to your doubts
Download App
Counselling Webinars
Online Certification Courses
NEET Question Papers
NEET 2025 Exam Date

Sitemap
Disclaimer
Comment Policy
Privacy Policy
Grievance Redressal

Copyright © 2024 Pathfinder Publishing Pvt Ltd.

National Eligibility cum Entrance Test

NEET 2025 Syllabus

Back to top