Pick a topic on the left, open a problem and check the solution hint by hint.
A source with emf $\varepsilon = 12$ V and internal resistance $r = 1$ ohm is connected to a resistor $R = 5$ ohm (the current in the circuit is $I = 2$ A). Find the voltage across the external part of the circuit.
A current source with emf $\varepsilon = 6$ V and internal resistance $r = 0.5$ ohm is connected to a resistor. The current in the circuit is $I = 4$ A. Find the resistance of the resistor.
A source of emf $\varepsilon = 12$ V with internal resistance $r = 1$ ohm is connected to an external resistance $R = 5$ ohm. Find the current in the circuit.