# The rheostat and the brightness of the bulbs

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1. Jun 10, 2017

### Asmaa Mohammad

1. The problem statement, all variables and given/known data
In the circuit shown in the figure, what will happen to the brightness of bulb A and bulb B when the wiper moves from point X to point Y?

2. Relevant equations

3. The attempt at a solution

When the wiper moves towards Y we get smaller resistance, hence the current intensity rises, so the brightness of A increases.
I think the brightness of B will increase too, as the current passing in its branch will increase.

I am not sure about my answer, what's your opinion?

2. Jun 10, 2017

### cnh1995

I agree with your answer.

3. Jun 10, 2017

### Asmaa Mohammad

I have just found that my book provides the answer, it is: brightness of bulb A decreases and the brightness of bulb B doesn't change, but there is no explanation.

4. Jun 10, 2017

### cnh1995

That's wrong.
Maybe this is the answer to some other similar question and the book just printed it at the wrong place.

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