Two similar springs P and Q have spring constants KP and KQ, such that KP>KQ. They are stretched, first by the same amount (case a), then by the same force (case b). The work done by the springs WPand WQ are related as, in case (a) and case (b), respectively :
WP> WQ; WQ> WP
Case (a) : w = 12kx2
wP=12Kpx2
WQ=12kQx2
∴kP>kQ,wP>wQ
Case (b) : w = 12 Fx
F=kPxP=kQwQ
∴xPxQ=kQkP
∴wPwQ=xPxQ=kQkP
∵kQ<kP,wP<wQ