Here’s How to Crack It
Before the switch is closed, there is no complete conducting pathway from the
positive terminal of the battery to the negative terminal, so no current flows through
the resistors. However, once the switch is closed, the resistance of the circuit is 2
Ω + 3 Ω + 5 Ω = 10 Ω, so the current in the circuit is. Often the
battery and its internal resistance are enclosed in a dotted line. See the following
example.