A 60 volt-10 watt bulb is operated at 100 volt-60 Hz a.c. The inducta…

$ P = VI$

$ I = \frac{P}{V} = \frac{1}{6}$

$R = \frac{V}{I} = 360\Omega$

$ \text{Impedance required is } Z = \frac{100}{1/6} = 600 \Omega$

$ X_L = \sqrt {z^2 - R^2} = 480\Omega$

$ L = \frac{X_L}{\omega} = \frac{480}{120\pi}= 1.28 H$