Chapter 34, Problem 28A

All bulbs are identical in the circuits shown below. An ammeter is connected next to the battery as shown. Rank the current readings in the ammeter, from greatest to least.

To determine

To Rank: The current readings from greatest to least.

Answer to Problem 28A

  $\text{C > B > A}$

Explanation of Solution

Introduction:

An ammeter is used to measure the amount of current flowing through a circuit.

The bulbs are identical but the number of bulbs is different in circuit. The bulbs are connected in parallel combination in B and C. With increase in number of branches in a parallel circuit, the equivalent resistance decreases which means the current would increase for the same voltage. The resistance of C is least followed by B and then A which implies that current reading would be maximum for C, then B and least for A.

Conclusion:

The rank of current readings from greatest to least:

  $\text{C > B > A}$