The extension of a wire by application of a load is 0.3 cm. The extension in a wire of same material, but of double the length and half the radius of cross-section, by the same load will be, in cm

Options

A. 0.3
B. 0.6
C. 1.2
D. 2.4

Answer

D

Explanation

Wires are of same material and equal forces is applied.
`(Deltal_(1))/(Deltal_(2)) = l_(1)/l_(2) xx (r_(2)/r_(1))^(2)`
`implies 0.3/(Deltal_(2) = l/(2l)=0.3xx8 = 2.4cm`