AP Physics 1 Question 278: Answer and Explanation

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Question: 278

5. Three identical light bulbs are connected to a source of emf, as shown in the diagram above. What will happen if the middle bulb burns out?

  • A. The light intensity of the other two bulbs will decrease (but they won't go out).
  • B. The light intensity of the other two bulbs will increase.
  • C. The light intensity of the other two bulbs will remain the same.
  • D. More current will be drawn from the source of emf.

Correct Answer: C

Explanation:

C

If each of the identical bulbs has resistance R, then the current through each bulb is ε/R. This is unchanged if the middle branch is taken out of the parallel circuit. (What will change is the total amount of current provided by the battery.)