Question

1. A student observes the relative brightness of bulbs A and B with the switch both open and closed. She finds the following: <(6 Switch open: Bulbs A and B have same brightness. Switch closed: Bulb A is brighter than when the switch was open; Bulb B does not light at all. a. With the switch closed, does current divide and recombine at the junctions? Does it divide evenly or unevenly? Explain. b. When the switch is closed, does the total resistance of the circuit change? If so, how? Explain. c. From this experiment, what can you infer about how the resistance of a bulb compares to that of a closed switch? Explain your reasoning.

Answer 1

when switch is open the same current flows through both bulb. But when switch is closed, then no current flows through bulb B because the current flows through short terminal. so current does not divide. when switch is open , then resistance of the circuit is the sum of resistance of both bulb. let the resistance of bulbs are R, then when switch is open then total resistance - aR. but when switch is closed, then circuit suffer only resistance of bulba. So, then tolal resistance - R. So resistance changes. © In closed circuit ie when switch is closed, then resistance of the circuit is equal to resistance of bulb A because in that care current only flows through bulb a.