Q. If $W$ be the weight of a body of density $\rho$ in vacuum then its apparent weight in air of density $\sigma$ is
A) $\frac{W\rho}{\sigma}$
B) $W\left( \frac{\rho}{\sigma} - 1 \right)$
C) $\frac{W}{\rho}\sigma$
D) $W\left( 1 - \frac{\sigma}{\rho} \right)$
Explanation
(d) Apparent weight in air = $W -$ upthrust $= V\rho g - V\sigma g$
$= V\rho g\left( 1 - \frac{\sigma}{\rho} \right) = W\left( 1 - \frac{\sigma}{\rho} \right)$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.