When a block of mass M is suspended by a long wire of length L, the length of the wire becomes (L + l).The elastic potential energy stored in the extended wire is [NEET 2019]

In stretching a wire, the work done against internal restoring force is stored as elastic potential energy inthe wire and is given byU=W=12× Force (F)×Elongation (/)=12Fl=12×Mg×l=12Mgl