Chapter 27.2, Problem 27.2QQ

With the switch in the circuit of Figure 27.4a closed, there is no current in R₂ because the current has an alternate zero-resistance path through the switch. There is current in R₁, and this current is measured with the ammeter (a device for measuring current) at the bottom of the circuit. If the switch is opened (Fig. 27.4b), there is current in R₂. What happens to the reading on the ammeter when the switch is opened? (a) The reading goes up. (b) The reading goes down. (c) The reading does not change.

Figure 27.4 (Quick Quiz 27.2) What happens when the switch is opened?