The EMF of the voltage source is 6.0 V. With an external resistance of the circuit 1.0 Ohm

The EMF of the voltage source is 6.0 V. With an external resistance of the circuit 1.0 Ohm, the current is 3.0 A. What will be the short-circuit current?

1) Find out the internal resistance of the specified voltage source: I = ε / (R + r), whence we express: r = ε / I – R, where ε is the EMF of the specified voltage source (ε = 6 V); I is the initial current in the circuit (I = 3 A); R – external resistance (R = 1 Ohm).

Calculation: r = ε / I – R = 6/3 – 1 = 2 – 1 = 1 Ohm.

2) We find out the short-circuit current (we take into account that at short-circuit R → 0): Isc = ε / r.

Calculation: Ikz = ε / r = 6/1 = 6 A.

Answer: The short-circuit current must be 6 A.