Electric lamp, filament resistance 20 Ohm, plugged into a network with a voltage of 220 V.

Electric lamp, filament resistance 20 Ohm, plugged into a network with a voltage of 220 V. What is the current power? What work will he do in 5 minutes of lamp glow?

Given:

U = 220 Volts – voltage of the electrical network;

R = 20 Ohm – lamp resistance;

t = 5 minutes = 300 seconds – time span.

It is required to determine the power consumption of the current W (Watt), and A (Joule) – the work done by the current during the time interval t.

Let’s find the current strength (according to Ohm’s law):

I = U / R = 220/20 = 11 Amperes.

Then the power of the electric current will be equal to:

W = U * I = 220 * 11 = 2420 watts.

The perfect work will be equal to:

A = W * t = 2420 * 300 = 726000 Joules = 726 kJ.

Answer: the power consumption is 2420 watts, the current will produce work equal to 726 kJ.