Constant voltage is applied between the two ends of a uniform metallic wire. The heat developed is doubled if –

Options

A. radius of the wire is doubled
B. length of the wire is doubled
C. both (a) and (b)
D. both length and radius of wire is halved

Answer

C

Explanation

The heat produced in the metallic wire is given using
`H = (v^(2)t)/( R)`
`R = rho (L)/(A)`
`H = (v^(2)+pi r^(2))/(rho L)`
Therefore, heat produced will be doubled it both length and the radius of the wire are doubled.