The current flowing through each bulb will be the same, regardless of their diff

Question

The current flowing through each bulb will be the same, regardless of their different individual resistances Learning Goal To practice Problem-Solving Strategy 26.1 Resistors in Series and Paralle Submit My Answers Give Up Two bulbs are connected in parallel across a source of emf 10.0 V with a negligible internal resistance. One bulb has a resistance of 3.0 and the other is 2.5 . A resistor R is connected in the circuit in series with the two bulbs. What value of R should be chosen in order to supply each bulb with a voltage of 2.4 V? Correct When you identify the type of resistor combination, you can infer some information on voltages across and currents through the resistors. Because the bulbs are connected in parallel, the potential difference is the same across each bulb. Because the two-bulb combination is in series with the unknown resistor R. the total current flowing through the parallel combination must equal the current through R. Keep in mind that R is your target variable in this problem EXECUTE the solution as follows Part C For what value of R would the potential difference across each of the bulbs be 2.4 V? Express your answer in ohms using three significant figures Hints Submit My Answers Give Up Incorrect, Iry Again; 3 attempts remaining Not quite. Check through your calculations, you may have made a rounding error or used the wrong number of significant figures

Explanation / Answer

current through R1, I1 = 2.4/3

through R2, I2 = 2.4/2.5

total current through battery = I1 + I2 = 1.76 A

R1 and R2 are in parallel,

R' = R1 R2 / (R1 + R2)

R' = 2.5 x 3 / (2.5 + 3 ) = 1.36 ohm

now R' and R are in series.

Req = R + 1.36

I Req = V

1.76 ( R + 1.36) = 10

R = 4.32 ohm ....Ans

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