Question

The heating coils rating at 220 volt and producing 50 cal/sec heat are available with the resistances $55\Omega,\mspace{6mu} 110\Omega,\mspace{6mu} 220\Omega$ and $440\Omega$. The heater of maximum power will be of

• A. $440\Omega$
• B. $220\Omega$
• C. $110\Omega$
• D. $55\Omega$

Answer 1

Answer: (D)

$55\Omega$

Answer 2

$\frac{H}{t} = \frac{V^{2}}{R}$⇒ $\frac{H}{t} \propto \frac{1}{R}$