Two steel wires having same length are suspended from a ceiling under the same load. If the ratio of their energy stored per unit volume is  1:4, the ratio of their diameters is

Energy=12×stress×strain×volumeEnergyvolume=12×stress×strain Enegy Density =E=12×stress2Y   Y=stressstrain    ⇒E=12×FA2Y=F22A2Y∴E1E2=d24d14          ∵A=πd24       ⇒14=d2d14    ⇒ d1d24=41    ⇒d1d2=21