Abhi koi question add nahi kiya. PYQ Bank se questions add karein.
PYQ Bank ›
Class 12 › Physics › Electric Charge and Field
CBSE2018Class Class 12 · Physics3 Marks · Short✅ Verified
A charge q is placed inside a sphere of radius \"a\" filled with water and another charge 2q is placed inside a cube of side \"2a\" which is vacuumed inside. Find the ratio of the flux linked with the sphere to that linked with the cube. (Take relative permittivity of water as 80)
✅ Answer & Solution
<b>Given:</b><br>• Sphere: charge q, medium = water, K = 80<br>• Cube: charge 2q, medium = vacuum, K = 1<br><br><b>Concept:</b><br>In a medium of dielectric constant K, Gauss\'s law becomes:<br>φ = q<sub>enclosed</sub>/(K·ε<sub>0</sub>)<br><br><b>Step 1: Flux through sphere (in water)</b><br>φ<sub>sphere</sub> = q/(K · ε<sub>0</sub>)<br>φ<sub>sphere</sub> = q/(80 · ε<sub>0</sub>)<br><br><b>Step 2: Flux through cube (in vacuum)</b><br>φ<sub>cube</sub> = 2q/ε<sub>0</sub><br><br><b>Step 3: Calculate ratio</b><br>φ<sub>sphere</sub>/φ<sub>cube</sub> = [q/(80·ε<sub>0</sub>)] ÷ [2q/ε<sub>0</sub>]<br><br>φ<sub>sphere</sub>/φ<sub>cube</sub> = q/(80·ε<sub>0</sub>) × ε<sub>0</sub>/(2q)<br><br>φ<sub>sphere</sub>/φ<sub>cube</sub> = 1/160<br><br><b>Answer:</b><br><b>φ<sub>sphere</sub> : φ<sub>cube</sub> = 1 : 160</b>
