Amount of charge flowing through a resistor?

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The discussion revolves around calculating the charge flowing through a resistor and the power dissipated in it. It is established that the current through the resistor is 3 mA, leading to a total charge of 600 coulombs over 200 seconds, using the formula Charge = Current x Time. For power dissipation, the correct formula is Power = Current² x Resistance, which results in a power dissipation of 720,000 mW or 720 W when using the given resistance of 2.0 kΩ. Participants clarify the distinction between current, charge, and power, emphasizing the importance of unit conversions, particularly from milli-Amps to Amps. Understanding these calculations is essential for exam preparation.
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Amount of charge flowing through a resistor?

the current through a resistor is 3 mA. What charge will flow through it in 200 seconds?

if the resistor has a resistance of 2.0 kΩ what will be the power dissipated in it?

for the first one, i have no idea. i can't seem to find any formula that is relavent to this so I am guess the answer is simple but I am missing a vital piece of information that would link the dots.

for the second one i was thinking the power disippated in the resistor would be the same as the resistance, becuase the resistance is stopping anything above 2.0 V to enter the resistor?

any help is appriated, this is for my exam tomorrow.
 
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druuuuuuuunnk said:
for the first one, i have no idea. i can't seem to find any formula that is relavent to this so I am guess the answer is simple but I am missing a vital piece of information that would link the dots.
What's the definition of current?

for the second one i was thinking the power disippated in the resistor would be the same as the resistance, becuase the resistance is stopping anything above 2.0 V to enter the resistor?
No, power is not the same as resistance. But the power dissipated depends on the current and the resistance. (Look it up!)
 


Doc Al said:
What's the definition of current?

"Electrical current is a measure of the amount of electrical charge transferred per unit time. It represents the flow of electrons through a conductive material.
Current is a scalar quantity (though in circuit analysis, the direction of current is relevant). The SI unit of electrical current is the ampere, defined as 1 coulomb/second"

so its 600 coulombs

im still confused about power, I've tried looking it up but it doesn't make any sense, is it the same as voltage?

so V=IxR

meaning 3 mA x 2 kΩ giving me 6 Volts that are being dissapated in the resistor
 


druuuuuuuunnk said:
"Electrical current is a measure of the amount of electrical charge transferred per unit time. It represents the flow of electrons through a conductive material.
Current is a scalar quantity (though in circuit analysis, the direction of current is relevant). The SI unit of electrical current is the ampere, defined as 1 coulomb/second"
Current = Charge/Time, thus Charge = Current * Time.

so its 600 coulombs
Redo that calculation.

im still confused about power, I've tried looking it up but it doesn't make any sense, is it the same as voltage?
No. Read: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elepow.html#c2"
 
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Ok so, to find the charge in 200 seconds. I multiply 3mA by 200 because charge = current*time

Giving me 600A ??

And for the second part I use Power = voltage * current

So the power dissipated in the resistor = 600 (current) * 2 (resistance) is this wrong ?
 


Actually for the second part, I'm meant to use power = current squared * resistance. So I'd get 720,000
 


druuuuuuuunnk said:
Ok so, to find the charge in 200 seconds. I multiply 3mA by 200 because charge = current*time

Giving me 600A ??
Careful: mA means milli-Amps = 10-3 Amps

(And the charge would be in Coulombs, not Amps.)

Same issue with your power calculation.
 


Ok, cheers mate!
 
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