A metal sphere weighing 60gm in air is suspended by a thread in an oil of specific gravity 0.6. If the tension in the thread is 55gmwt, the specific gravity of the metal sphere is

In oil Tension in the thread T = 55 gwt

mg = 55g

m = 55gm

weight of metal sphere in oil ${\text{w}}_2=55\text{gm}$

R.D of oil $=\frac{60-55}{60-{\text{w}}_{\text{3}}}$

$0.6=\frac{5}{60-{\text{w}}_{\text{3}}}$

$36-0.6{\text{w}}_{\text{3}}=5$

${\text{w}}_3=\frac{31}{0.6}=51.67\text{gm}$

R.D of metal sphere$\text{=}\frac{60}{60-51.67}$

$=\frac{60}{8.33}=7.2$