Chapter 23.2, Problem 26PP

To determine

The bulbs that will burn brightest from the given circuit.

Answer to Problem 26PP

Bulb with resistances $R_{12}$ and $R_{13}$ .

Explanation of Solution

Introduction:

The potential in parallel combination remains same while the current remains same in series. Also, in the series combination of the resistances, the net resistance is always greater than the individual resistances. While in the parallel combination of the resistances, the net resistance is always less than the individual resistances.

Now, the bulb with less resistance or with the great potential difference across it, will burn brightest.

Consider the given circuit, the bulb with resistances $R_{12}$ and $R_{13}$ are connected in parallel while all other bulbs are in series. Then the potential difference across the parallel combination of those two resistors will be greater than the across the other bulbs since the net resistance of those two resistors will be less.

Conclusion:

Hence, the bulb with resistances $R_{12}$ and $R_{13}$ will burn brightest.