Q. Two identical charged spheres are suspended by strings of equal lengths. The stings make an angle of $30^{o}$ with each other. When suspended in a liquid of density $0.8g\ cm^{- 3},$ the angle remains the same. If density of the material of the sphere is $1.6g\ cm^{- 3},$ the dielectric constant of the liquid is
A) 1
B) 4
C) 3
D) 2
Explanation
(d) $K = \frac{\rho}{\rho - \sigma} = \frac{1.6}{1.6 - 0.8} = 2$
$\rho \rightarrow$ density of sphere, $\sigma \rightarrow$ density of liquid
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.