Question

Mixed Review 21.108 2 of 42> tants Part A Consider the circuit shown in the figure(Figure 1), in which three lights, each with a resistance R, are connected in series. The circuit also contains an open switch Does the current supplied by the battery increase, decrease, or remain the same when the switch is closed? O increase decrease remain the same Submit Request Answer Figure 1 of 1 ? Part B Choose the best explanation from among the following The current decreases because only two resistors can draw current from the battery when the switch is closed Closing the switch makes no difference to the current since the second resistor is still connected to the battery as before 1 2 Closing the switch shorts out the second resistor, decreases the total resistance of the circuit, and increases the cur rent. Submit Request Answer

Answer 1

when switch is open

equivalent resistance Req = R1 + R2 + R3 = R + R + R = 3R

current flowing in circuit I = E/Req = E/(3R)

when switch is closed

the R2 is shortvircuted

equivalent resistance Req = R1 + R2 = R + R = 2R

current flowing in circuit I' = E/Req = E/(2R)

I < I

part(A)

increase

part(B)

closing the switch shorts out the second resistor , decreases the total resistance
of the circuit and decreases the current