Q. A piece of solid weighs 120 g in air, 80 g in water and 60 g in a liquid. The relative density of the solid and that of the liquid are respectively
A) 3,2
B) $2,\frac{3}{4}$
C) $\frac{3}{2},2$
D) $4,3$
Explanation
(c) Relative density of solid
$= \frac{weight\ in\ air}{weight\ in\ air - weight\ in\ water}$
⟹ Relative density of solid $= \frac{120}{120 - 80} = \frac{120}{40} = 3$
Relative density of liquid $= \frac{weight\ in\ air - weight\ in\ liquid\ }{weight\ in\ air - weight\ in\ water}$
⟹ Relative density of liquid
$= \frac{120 - 60}{120 - 80} = \frac{60}{40} = \frac{3}{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.