Chapter 23.2, Problem 33SSC

To determine

To identify: whether bulbs 2 and 3 are identical or not.

Explanation of Solution

Introduction:

If the resistor is added to the circuit at the point $C$ , the equivalent resistance of the branch will increase. But the total resistance of the circuit will decrease since the bulbs are connected in parallel.

It is given that $V_2=3.8\text{volt}$ and $V_3=4.2\text{Volt}$ .

Since the bulbs are connected in series, same current flows through them. The power dissipation is given by

  $P=VI$

Here, $V$ and $I$ are voltage drop and current.

Since the voltage drops across the bulbs are different, the power dissipation or the brightness of the bulbs will be different. Thus, one of the bulbs will be brighter than other.

Conclusion:

Hence, the bulb 2 and 3 are not identical.