When a metal wire elongates by hanging a load `Mg` on it the gravitational potential energy of mass `M` decrease by `Mgl`. This energy appears

Options

A. as elastic potential enelrgy apears
B. as thermal energy completely
C. half as elastic potential energy and half as thermal energy
D. as kinetic energy of the load completely.

Answer

C

Explanation

When a metal wire elongates by hanging a load `Mg` on it decrease in potential energy of the load `=Mgl`
where `l=` elongation in metal wire.
Elastic potential energy stored in stretched wire `=1/2xxMgl`
Difference of `Mgl` and `1/1Mgl` appears as heat energy in the stretched wire.
`:.` Energy appearing as heast
`=Mgl-1/2Mgl=1/2Mgl`