Determine the rated current in a 100W lamp at a rated voltage of 220W. What is its electrical resistance?

Given:

W = 100 watts – the power of the electric lamp;

U = 220 Volts – nominal voltage of the electrical network.

It is required to determine the rated current I (Ampere) and electrical resistance R (Ohm).

Let’s find the rated current:

I = W / U = 100/220 = 0.45 Ampere.

Then the electrical resistance of the lamp will be equal to:

R = U / I = 220 / 0.45 = 488.9 Ohm.

Answer: the nominal current is 0.45 amperes, the electrical resistance of the lamp is 488.9 ohms.