How many amperes are required to light an ordinary 40-watt, 120-volt incandescent lamp? (Assume thepower factor to be 1.0)

Correct option is A

​$$\text{Given:} \\\text{Power (P) = 40 W} \\\text{Voltage (V) = 120 V} \\\text{Power factor (pf) = 1.0}\\\text{The formula for current } I \text{ in terms of power } P, \text{ voltage } V, \text{ and power factor } pf \text{ is:} \\I = \frac{P}{V \times pf}\\I = \frac{40}{120 \times 1.0} \\I = \frac{40}{120} \\I = 0.3333 \, \text{A}$$​​