The EMF of the current source is 4.5 V, the internal resistance is 1 Ohm. Determine the current in the circuit

| August 9, 2021 | education

The EMF of the current source is 4.5 V, the internal resistance is 1 Ohm. Determine the current in the circuit with a resistor of 8 ohms. What is the voltage across the resistor?

EMF = 4.5 V.

r = 1 ohm.

R = 8 ohms.

I -?

U -?

According to Ohm’s law for a closed loop, the current in the circuit I is directly proportional to the electromotive force of the EMF current source and is inversely proportional to the sum of the external resistance R and the internal resistance of the current source r: I = EMF / (R + r).

I = 4.5 V / (8 Ohm + 1 Ohm) = 0.5 A.

We express the voltage across the resistor U from Ohm’s law for a section of the circuit: I = U / R.

U = I * R.

U = 0.5 A * 8 Ohm = 4 V.

Answer: the current in the circuit will be I = 0.5 A, the voltage across the resistor will be U = 4 V.



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