A cubical copper block has eahc side 2.0 cm. It is suspended by a string and submerged in oil of density `820 kg m^(-3)`. Calculate the tension in the string.
(density of copper = `8920 kg m^(-3)`)

Explanation

Tension = true weight - upthrust due to oil
`= V rho g - V sigma g = V (rho - sigma) g`
`=(2 xx 10^(-2))^(3) xx (8920 - 820) xx 10 = 8 xx 10^(-6) xx 8100 xx 10`.