Chapter 19, Problem 8Q

To determine

The effect on the overall resistance of the room’s electric circuit when an additional bulb of $100\text{W}$ is added.

Explanation of Solution

Given information:

Power across the first bulb, $P_1=60\text{W}$

Power across the additional bulb, $P_2=100\text{W}$

Introduction:

Write the expression to calculate the total resistance of the circuit in parallel connection.

  $\frac{1}{R_{\text{P}}}=\frac{1}{R_1}+\frac{1}{R_2}$

Where,

• The total resistance of the circuit is $R_{\text{P}}$ in parallel connection.

When resistors are connected in series, the overall resistance of the circuit increases and the overall resistance of the circuit decreases when they are connected in parallel.

When the additional bulb of $100\text{W}$ is turned on, the overall resistance of the circuit decreases and the current increase according to Ohm’s law.

Conclusion:

Therefore, the overall resistance of the room’s electric circuit decreases.