# AAMC QPack Physics #28

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#### 77deuce

##### Full Member
5+ Year Member  1. But when I was reviewing the question I started to wonder if the resistance would decrease since R=V/I, and voltage stayed the same (according to the explanation) while the current increased.

This seems like an obvious yes, but I'm not sure since the explanation says "the only effect on the apparatus of electron ejection from the cathode is the current in the circuit."

2. If the resistance did decrease, then would that be the resistance across the photodiode?

3. Also, since the current did increase in the circuit, then wouldn't the voltage drop across the resistor increase since V=IR?

I'm not very well-versed with photoelectrics, obviously. I'm not sure if my questions even make sense.

#### aldol16

##### Full Member
7+ Year Member
1. But when I was reviewing the question I started to wonder if the resistance would decrease since R=V/I, and voltage stayed the same (according to the explanation) while the current increased.

This seems like an obvious yes, but I'm not sure since the explanation says "the only effect on the apparatus of electron ejection from the cathode is the current in the circuit."

The current didn't really increase. If electrons are not ejected from the cathode, then there is no current, period. So before, there was no current. Now, once electrons start getting ejected, there is a current. So it's not really an increase. Applying R = V/I doesn't work when I = 0, so you can't compare I = x to I = 0.

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