NEET 2026 Preparation Tips for Chemistry, Biology and Physics

Huygens Principle MCQ - Practice Questions with Answers

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

Eligibility Criteria

Application Process

Preparation Tips

Counselling Process

College Predictor

College Predictor

Accepting Colleges

Quick Facts

12 Questions around this concept.

Solve by difficulty

The following figure represents a wavefront AB that passes from air to another transparent medium and produces a new wavefront CD after refraction. The refractive index of the medium is (PQ is the boundary between air and the medium).

A

$\frac{\cos \theta_1}{\cos \theta_4}$

B

$\frac{\cos \theta_4}{\cos \theta_1}$

C

$\frac{\sin \theta_1}{\sin \theta_4}$

D

$\frac{\sin \theta_2}{\sin \theta_3}$

Concepts Covered - 1

Huygens principle

According to the Huygens principle , Every point on the given wavefront acts as a source of a new disturbance called secondary wavelengths. And a common tangent to these secondary wavelets in the forward direction at any instant gives the new wavefront at that instant as shown in the below figure. This is called secondary wavefront.

Reflection of plane wave using Huygens principle

The Lightwave will follow the Laws of Reflection. Let's understand this with the help of the Huygens principle.

Consider a plane wavefronts travels towards a plane reflecting surface as shown in the figure.

Let AB and CD as the incident and reflected wavefronts respectively.

The angle of incidence i and angle of reflection r are the angles made by incidence and reflected ray respectively with the normal and these are also the angles made by the wavefronts AB and CD respectively with the reflecting surface.

Let at t=0 wave is at A and at $t=\tau$ wave is at C.

if v₁ is the velocity of the wave $BC=AD=v_1\tau$

And as $\Delta ABC \cong \Delta ADC$ So we get $i=r$ .

This verifies the first law of reflection which states that the angle of incidence i and angle of reflection r are always equal.

Similarly from the figure, we can say that the incident wavefront, the reflected wavefront and normal lie in the same plane.

This again verifies the second law of reflection.

Therefore, the two laws of Reflection are verified using Huygens's Principle.

Refraction of plane wave using Huygens principle

The Lightwave will follow the Laws of Refraction. Let's understand this with the help of the Huygens principle.

Consider a plane wavefronts travels towards a plane AC as shown in the above figure.

Let AB and CD as the incident and refracted wavefronts respectively.

The angle of incidence i and angle of refraction r are the angles made by incidence and refracted ray respectively with the normal and these are also the angles made by the wavefronts AB and CD respectively with the surface AC.

Let at t=0 wave is at A and at $t=\tau$ wave is at C.

if v₁ is the velocity of the wave in medium 1 then $BC=v_1\tau$

similarly v₂ is the velocity of the wave in the medium 2 then $AD=v_2\tau$

$For \ \ \Delta ABC \rightarrow sin(i)= \frac{BC}{AC}=\frac{v_1\tau }{AC}$

similarly $For \ \ \Delta ACD \rightarrow sin(r)= \frac{AD}{AC}=\frac{v_2\tau }{AC}$

So we get $\frac{ sin(i)}{ sin(r)}=\frac{v_1\tau }{v_2\tau}=\frac{v_1}{v_2}$

And we know $\mu \ \ \alpha \ \ v$

So we get

$\frac{ sin(i)}{ sin(r)} =\frac{v_1}{v_2}=\frac{\mu _2}{\mu _1}=\mu _{21}=constant$

This verifies the first law of refraction.

Similarly from the figure, we can say that the incident wavefront, the refracted wavefront and normal lie in the same plane.

This again verifies the second law of Refraction.

Therefore, the two laws of Refraction are verified using Huygens's Principle.

Study it with Videos

Huygens principle

Study other Related Concepts

Huygens Principle 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

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

Amity University-Noida Health and Allied Sciences Admissions

Amongst top 3% universities globally (QS Rankings) | Wide Range of scholarships available

MAHE Manipal BSc Nursing 2026

NAAC A++ Accredited | Accorded institution of Eminence by Govt. of India | NIRF Rank #3

SCSVMV Deemed to be University | AHA Admissions 2026

Alied Health Sciences at SCSVMV | NAAC 'A' Grade | AICTE & UGC Aproved | 100% Placement Support | Merit-based Scholarships

Virohan Allied & Healthcare Programs

Allied & Healthcare programs | 20+ Partner Universities & Institutes | 98% placement record

SRM Kattankulathur Dental College Admissions 2026

Ranked #19 by NIRF, NAAC A++ Accredited | Recognized by dental council of India

SRM Medical College Admissions 2026

Ranked #18 by NIRF, NAAC A++ Accredited | Unmatched clinical exposure with over 7 lakh patients yearly

View all Application Forms

Student Community: Where Questions Find Answers

Ask and get expert answers on exams, counselling, admissions, careers, and study options.

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