Q 12-08-030JEE MainJEE Main 2026 (6 Apr, Shift 1)Easy
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 ______.
Answer: (B) $I_0$
A point source radiates equally in all directions, so $I = \dfrac{P}{4\pi r^2}$ depends only on the distance. On the same sphere ($r = L$) the intensity is still $I_0$.
Solution by Sreeraj P, M.Sc Physics