JEE Main 2025 · PhysicsNumerical answerNumerical valueMediumCalculation

JEE Main 4 April 2025, Shift 2, Physics Q47

Question 47 of 75 in this shift, Physics question 22 of 25, Section B.

If an optical medium possesses a relative permeability of

\frac{10}{\pi}

and relative permittivity of

\frac{1}{0.0885}

, then the velocity of light is greater in vacuum than that in this medium by __________ times. (

\mu_0=4\pi\times10^{-7}

H/m,

\epsilon_0=8.85\times10^{-12}

F/m,

c=3\times10^8

m/s)

Official answer

NTA final key.

Chapter: Electromagnetic Waves
Topic: Refraction and Snell's Law
Idea tested: Refractive Index and Speed

Same idea in other shifts

Asked 3× in all

7 Apr 2025, Shift 2 · Q41Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Refractive…EasyAssertion–reason
25 Jun 2022, Shift 1 · Q49The difference of speed of light in the two media A and B ( $v_A-v_B$ ) is $2.6\times10^7$ m/s. If the refractive index of medium B is 1.47,…MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.