A wire is suspended vertically from a rigid support. When loaded with a steel weight in air, the wire extends by `16cm`. When the weight is completely immersed in Water, the extension is reduced to `14 cm`. The relative density of the material of the weight is

Options

A. `2g//cm^(3)`
B. `6g//cm^(3)`
C. `8g//cm^(3)`
D. `16 g//cm^(3)`

Answer

C

Explanation

`Y=(Fl)/(a/_\l), Y, l` and `a` constants
`:. F=/_\l`
In the first case `Vrhog=16`
In the second case `(Vrho-Vxx1xxg)=14`
Dividing `=(Vg(rho-1))/(Vgrho)=14/16=7/8`
or `(rho-1)/rho=7/8` or `8rho-7rho` or `rho=8g//cm^(3)`