The work done in stretching a spring of force constant k from lengt...

The work done in stretching a spring of force constant k from length \(\ell_{1}\) and \(\ell_{2}\) is

A. \(k(\ell_{2}^{2} - \ell_{1}^{2})\)

B. \(\frac{1}{2}k(\ell_{2}^{2} - \ell_{1}^{2})\)

C. \(k(\ell_{2} - \ell_{1})\)

D. \(\frac{k}{2}(\ell_{2} + \ell_{1})\)