The lamp is designed for a voltage of 220 V. It was plugged into a network with a voltage of 110 V.

The lamp is designed for a voltage of 220 V. It was plugged into a network with a voltage of 110 V. How many times will the lamp power decrease?

Given:

U1 = 220 Volts – the voltage for which the light bulb is designed;

U2 = 110 Volts – the voltage that was applied to the bulbs.

It is required to find the power ratio W2 / W1 of the light bulb.

In the first case, the power of the light bulb will be equal to:

W1 = U1 * I.

In the second case, the power of the light bulb will be equal to:

W2 = U2 * I.

Then:

W2 / W1 = U2 * I / (U1 * I) = U2 / U1 = 110/220 = 0.5.

Answer: the power of the light bulb will decrease by 0.5 times.