Discussion
Two 60 W, 120 V light bulbs are connected across a 120 V supply as shown in figure below. The current drawn by each bulb will be :
Answer: D
Each bulb draws 0.5 A.
The bulbs are in parallel across the 120 V supply, so each receives its full rated voltage and draws its rated power of 60 W.
\[ I = \frac{P}{V} = \frac{60}{120} = 0.5\ \text{A} \]
Each bulb's resistance is \(120^{2}/60 = 240\ \Omega\), which gives the same current, \(120/240 = 0.5\) A. 1 A is the total drawn from the supply by the two bulbs together, not the current in each, and 1.5 A or 2 A would mean the bulbs were running well above their rating.
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