Q. Two wires of the same material and having same uniform area of cross-section are connected in series in an electrical circuit. The masses of the wires are $m\ and\ 2m$. When a current $I$flows in the circuit, the heats produced by them in a given time are in ratio
A) 2 : 1
B) 1 : 2
C) 4 : 1
D) 1 : 4
Explanation
(b) $\frac{R_{1}}{R_{2}} = \frac{m_{1}}{a_{1}^{2}} \times \frac{a_{2}^{2}}{m_{2}}$
$= \left( \ \frac{m1}{m2} \right)\left( \ \frac{a_{2}}{a_{1}} \right)^{2} = \left( \ \frac{1}{2} \right)(1)^{2} = \frac{1}{2}$
$\ \frac{Q_{1}}{Q_{2}} = \frac{I^{2}R_{1}t}{I^{2}R^{2}t} = \frac{1}{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.