Physics · Electromagnetic Waves

JEE Main 2026 — 6 April, Morning Shift — Question 11

A point light source emits E.M. waves in free space. A detector, placed at a distance of L m, measures the intensity as $I_0$ . The detector is now shifted to another location on the same spherical surface ensuring the angle between original location and new location as $45^\circ$ . The measured intensity at new location will be ______.

Option A:
$I_0/4$
Option B:
$I_0$
Correct
Option C:
$I_0/\sqrt{2}$
Option D:
$I_0/2$

Answer: B

Step-by-step solution

Intensity from a point source is isotropic, depending only on distance. Since both points are on same spherical surface (same distance from source), intensity remains $I_0$ .

Answer key and solution verified before publishing.

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Exam: JEE Main 2026
Paper: 6 April, Morning Shift
Subject: Physics
Chapter: Electromagnetic Waves
Topic: Power , Energy and Intensity of EM Waves