In a rheostat, a resistance of 200 ohms flows a current of 200 mA. determine the work of electric current in 1 minute
September 30, 2021 | education
| Given:
R = 200 Ohm – rheostat resistance;
I = 200 mA = 0.2 Ampere – current flowing in the rheostat;
t = 1 minute = 60 seconds – time span.
It is required to determine A (Joule) – the work of an electric current for a time interval t.
Let’s find the voltage of the electrical circuit (according to Ohm’s law):
U = I * R.
Then the current power will be equal to:
W = U * I = I * R * I = I ^ 2 * R.
The work of the electric current will be equal to:
A = W * t = I ^ 2 * R * t;
A = 0.2 ^ 2 * 200 * 60 = 0.04 * 200 * 60 = 8 * 60 = 480 Joules (0.48 kJ).
Answer: in 1 minute, the electric current passing through the rheostat performed work equal to 480 Joules.
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