A metallic sphere weighs `210g` in air, 180 g in water and 120 g in an unknown liquid. Find the density of metal and of liquid.

Options

A. metal is 3
B. metal is 7
C. liquid is 7
D. liquid is 1/3

Explanation

`W = v(rho_(m) - sigma w) g`
`180 = V( rho_(m) - sigma _(w)) g " "` (1)
` 120 = V(rho_(m) - sigma _(t))g " "` (2)
`210 =V_(rhomg)`
From (1) and (3)
`180/210 = (rho_(m) - rho_(w))/(rho_(m)) rArr rho_(m) = 7 sigma_(w)`
From (1) (2) and (3)
`180/120 - (rho_(m) - sigma_(w))/(rho_(m) - sigma_(t))`
`3/2=(7/3 sigma _(t)-sigma_(w))/(7/3 sigma_(t) - sigma_(i)) rArr rho_(t) = 3 sigma _(w)`