Question

Two heater wires of equal length are first connected in series and then in parallel. The ratio of heat produced in the two cases is

• A. 2 : 1
• B. 1 : 2
• C. 4 : 1
• D. 1 : 4

Answer 1

Answer: (D)

1 : 4

Answer 2

Power consumed means heat produced. For constant potential difference $P_{\text{consumed}} = \text{Heat} \propto \frac{1}{R_{eq}}$

$\therefore\frac{H_{1}}{H_{2}} = \frac{R_{2}}{R_{1}} = \frac{R/2}{2R} = \frac{1}{4}$

(Since $R_{2} = \frac{R.R}{R + R} = \frac{R}{2}$and $R_{1} = R + R = 2R)$