Question

The same mass of copper is drawn into two wires 2mm and 3mm thick,. The two wires are connected in series and current is passed through them. The ratio of heats produced in the two wires is-

Answer 1

$H=I^{2} RT$-----   1

LET RESISTANCE OF 2MM WIRE BE R1 AND OF 3MM BE R2

$R=\rho \frac{L}{A}$------  2

therefore rho gets cut and L gets cut

therefore-

$\frac{R1}{R2} =\frac{A2}{A1}$            [WHERE A1=2MM AND A2 = 3MM]

$\frac{R1}{R2} =\frac{3}{2}$-------- 3

$\frac{H1}{H2} =\frac{I1^{2} R1T}{I2^{2} R2T}$

T AND I GETS CUT

THEREFORE

$\frac{H1}{H2} =\frac{3}{2}$