A 220V, 100W bulb is connected to a 110V source. Calculate the power consumed by the bulb.

Electrical power is the rate at which electrical energy is dissipated into other forms of energy.

P= VI =I²R=$\frac{{\mathrm{V}}^2}{\mathrm{R}}$

Given: V = 220 V, P = 100 W, and actual voltage ${\mathrm{V}}^{|}$=110V

$\mathrm{R}=\frac{{\mathrm{V}}^2}{\mathrm{P}}$

   $=\frac{{220}^2}{100}$

   $=484\Omega$

The power consumed by the bulb for V=110 V:

P=$\frac{{V^{|}}^2}{R}$

  $=\frac{{110}^2}{484}$

  $=25 W$