Question

Two bulbs of equal power are connected in parallel and they totally consume $110 \, W$ at $220 \, V$ . The resistances of each bulb is

• A. $550 \, \Omega$
• B. $440 \, \Omega$
• C. $330 \, \Omega$
• D. $880 \, \Omega$

Answer 1

Answer: (D)

Bulbs are connected in parallel and they totally consume $110 \, W$ at $220 \, V$
Net power, $P_{n e t}=P_{1}+P_{2}$
$P+P=110 \, W \, \, \, \left\{\because P_{1} = P_{2} = P\right\}$
$2P=110 \, W\Rightarrow P=55 \, W$
We know that,
$P=\frac{V^{2}}{R}$
$55=\frac{\left(220\right)^{2}}{R}$
$R=\frac{\left(220\right)^{2}}{55}=\frac{220 \times 220}{55}=880 \, \Omega$