A copper wire having cross-sectional area `0.5mm^(2)` and a length 0.1 m is initially at `25^(@)C` and is thennallyinsulated from the surrounding. If a current of 10 A is set up in this wire,
(a) Find the time in which the wire will start melting. The change ofresistancewith the temperature of the wire maybe neglected.
(b) What will be the time taken iflength of the wire is doubled? Given for copper wire, its density `9xx10^(3) kg//^(3)` specific heat `9xx10^(-2) kcal//kg .^(@)C` melting point `1075^(@)C` and specific resistance `1.6 xx 10^(-8) Omega-m`