Calculating Charge and Current in a Resistor Circuit

AI Thread Summary
A 23-ohm resistor connected to a 4.4V battery raises the question of how much charge passes through it after 5 seconds. The current can be calculated using Ohm's Law, I = ΔV/R, resulting in I = 4.4V/23Ω. The confusion arises regarding whether the current is constant, with some participants mistakenly thinking a capacitor is involved. Ultimately, the current is indeed constant in this simple circuit, allowing for straightforward calculations of charge over time. The discussion concludes with a participant successfully determining the relationship between current and charge.
whitehorsey
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1. At time t = 0, a 23 ohms resistor is linked to a 4.4V battery. How much charge has gone through the resistor after 5 seconds?

2. Q = CΔV
ΔV = IR

3. ΔV = IR
I = ΔV/R
= 4.4/24 A.

I'm not sure what to do next.
 
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whitehorsey said:
1. At time t = 0, a 23 ohms resistor is linked to a 4.4V battery. How much charge has gone through the resistor after 5 seconds?

2. Q = CΔV
ΔV = IR

3. ΔV = IR
I = ΔV/R
= 4.4/24 A.

I'm not sure what to do next.

Q = ∫I dt
 
whitehorsey said:
1. At time t = 0, a 23 ohms resistor is linked to a 4.4V battery. How much charge has gone through the resistor after 5 seconds?

2. Q = CΔV
ΔV = IR

3. ΔV = IR
I = ΔV/R
= 4.4/24 A.

I'm not sure what to do next.

How did the 23Ω become a 24 when you wrote it down in the formula?

Anyway, what is the relationship between a constant current, charge and time?
 
Note that the current is not constant in this case!
 
vanhees71 said:
Note that the current is not constant in this case!

EDIT: At first, I thought I'd made a ghastly mistake because I'd forgotten a capacitor or something. But this is just a simple circuit with a battery and a resistor. Why can't the current be assumed to be constant?
 
vanhees71 said:
Note that the current is not constant in this case!

There is only a resistor and a battery, how is the current not constant?
There is no indication of capacitance in the question details.
 
The current is constaant. Find the current and find that charge using the time given. Straight foward!
 
Ok, then I didn't understand the question. I thought there is a resistor and a capacitor. So the Q=CU equation doesn't make any sense.
 
whitehorsey said:
1. At time t = 0, a 23 ohms resistor is linked to a 4.4V battery. How much charge has gone through the resistor after 5 seconds?

2. Q = CΔV
ΔV = IR

3. ΔV = IR
I = ΔV/R
= 4.4/24 A.

I'm not sure what to do next.

1 A = ?? coulombs/sec
 
  • #10
I figured it out. Thanks guys!
 
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