The battery has an EMF of 12 V. The current in the circuit is 4 A, and the voltage

| September 23, 2021 | education

The battery has an EMF of 12 V. The current in the circuit is 4 A, and the voltage at the terminals is 11 V. Determine the short-circuit current.

U = 11 V.

I = 4 A.

EMF = 12 V.

Ikor -?

A short circuit is a circuit state in which there is no external resistance R = 0, the current reaches the maximum possible value.

Ohm’s law for a closed circuit is: I = EMF / (R + r), where I is the current in the circuit, EMF is the electromotive force of the current source, R is the external resistance of the circuit, r is the internal resistance of the current source.

R + r = EMF / I.

r = EMF / I – R.

In case of short circuit R = 0, Icor = EMF / r.

Let’s write Ohm’s law for a section of the circuit: I = U / R.

The external resistance of the circuit R is found by the formula: R = U / I.

R = 11 V / 4 A = 2.75 Ohm.

r = 12V / 4A – 2.75 Ohm = 0.25 Ohm.

Icor = 12 V / 0.25 Ohm = 48 A.

Answer: with a short circuit, the current strength is Icor = 48 A.



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