The battery has an EMF of 12 V. The current in the circuit is 5A, and the voltage at the terminals is 10 V.

The battery has an EMF of 12 V. The current in the circuit is 5A, and the voltage at the terminals is 10 V. Determine the short-circuit current.

In the event of a short circuit, the current strength will be determined by the EMF of the battery and the internal resistance of the battery: I short circuit = E / r.

The internal resistance of the battery – r, can be expressed from Ohm’s law for a complete circuit:

E = U + I * r;

r = (E – U) / I = (12-10) / 5 = 2/5 = 0.4 ohm.

I short-circuit = 12 / 0.4 = 30 A.

Answer: short-circuit current 5 A.