Two springs A and B have force constants k1 and k2 respectively. The ratio of work done on A to that done on B when they are stretched by the same force is
k2k1
When the springs are stretched by the same force F, let the extensions be x1 and x2.
So, F=k1x1=k2x2⇒x1x2=k2k1
Now, ratio of work done, W1W2=12k1x2112k2x22=k1x1×x1k2x2×x2=x1x2=k2k1
Hence, the correct choice is (c).