A spring when stretched up to 2 cm has potential energy U. If it is stretched up to 10 cm, potential energy would be
U /25
U/5
5 U
25U
The potential energy Up of spring is given by Up=12kx2 In first case, U=12k(2)2=2k or k=U/2 In second case, Up=12k(10)2=12×U2×(10)2=25U