Question

A cubical copper block has each side $2.0\, cm$. It is suspended by a string and submerged in oil of density $820\, kg / m ^{3}$. The tension in the string is (density of copper $8920\, kg / m ^{3}, g=10\, m / s ^{2}$ )

• A. 0.648 N
• B. 0.712 N
• C. 0.066 N
• D. 1.37 N

Answer 1

Answer: (A)

Tension, $T=m g-$ buoyant force
$=V \rho g-V \sigma g=V(\rho-\sigma) g=l^{3}(\rho-\sigma) g$
$=8 \times 10^{-6}(8920-820) \times 10$
$=0.648\, N$