Thanks for the help. For the next midterm, like the last, we\'ll be including cu

Question

Thanks for the help.

For the next midterm, like the last, we'll be including cumulative questions on material from previous units. We'll be focusing on the same topics related to electricity (adding electric fields and forces as vectors, the link between work and electric potential, and the distribution of positive and negative charges in objects) For our review of the second unit of the course, we'll be focusing on the direction of magnetic forces, changes in circuits (including switched and broken bulbs), and the difference between external and induced magnetic fields and flux. We're starting this quiz with two review questions, one for each unit. Here's the first: Three bulbs with equal resistances are arranged in a circuit as shown. First, switch S is open. What can you say about the brightnesses of bulbs A and B after switch S is closed? The brightnesses of bulbs A and B will increase. The brightness of bulb A will increase and the brightness of bulb B will not change. The brightnesses of bulbs A and B will decrease. The brightness of bulb A will not change and the brightness of bulb B will decrease. The brightness of bulb A will decrease and the brightness of bulb B will increase. O The brightness of bulb A will increase and the brightness of bulb B will decrease. The brightness of bulb A will decrease and the brightness of bulb B will not change. The brightnesses of bulbs A and B will not change. The brightness of bulb A will not change and the brightness of bulb B will increase.

Explanation / Answer

when switch is open

VA = VB = e

IA = IB = e / R

when switch is closed,

VA = VB = VC = e

IA = IB = IC = e / R

As we can see , current remains same.

Ans: Brightness of bulbs will not change.

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