Q. A body weight 50 g in air and 40 g in water. How much would it weigh in a liquid of specific gravity 1.5?
A) 30 g
B) 35 g
C) 65 g
D) 45 g
Explanation
(b) $\frac{\sigma_{L}}{\sigma_{W}} = \frac{Upthrust\ on\ body\ in\ liquid}{Upthrust\ on\ body\ in\ water}$
$\frac{1.5}{1} = \frac{x}{(50 - 40)g}$
⟹ $x = 15g$
$\therefore Upthrust\ on\ body\ in\ liquid = 15g$
Weight on the body $= 50g$
Hence, body will weight $(50 - 15) = 35\ g\ in\ the\ liquid$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.