A metal wire of length L, area of cross-section A and young's modulus `Y` is stretched by a variable force `F` such that `F` is always slightly greater than the elastic forces of resistance in the wire. When the elongation of the wire is `l`

Options

A. the work done by F is `(YAl^2)/(2L)`
B. the work done by F is `(YAl^2)/(L)`
C. the elastic potential energy stored in the wire is `(Yal^2)/(2L)`
D. no heat is produced during the elongation

Answer

B