Calculating Charge in a 9V, 12W Radio

I got 5.916x10^2.In summary, the person calculated the current and charge for a 9.0 V, 12.0 W radio running for 1.33 hours. They used the equations Power= potential difference/resistance and I²=Power/Resistance to determine the current and then multiplied it by the time in seconds to find the total charge. After realizing a mistake, the correct charge was calculated to be 5.916x10^2 coulombs.
  • #1
aaronmilk3
12
0
A person runs a 9.0 V, 12.0 W radio for 1.33 hours. How many coulombs of charge pass through the wires in the radio during this time?

I used Power= pot difference/Resistance = 9v/120w=7.5e-2

I=current
Then I used I²=P/R= 120v/7.5e-2 = 1.6e3
I=40A

1.33h*60mins*60secs = 4.788e3

Q=Charge
Then Q=It = (40A)(4.788e3 secs) = 1.92e5 but this is not the right answer.

Any help would be great. Thanks!
 
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  • #2
I made a mistake with the first equations it is P=pot diff²/R => R= pot diff²/R so I ended up recalculating and I got 6.384x10^4 but it is still not right.
 
  • #3
Never mind I figured out
 

1. How do I calculate the charge in a 9V, 12W radio?

To calculate the charge in a 9V, 12W radio, you need to use the formula Q = P/V, where Q is the charge in coulombs, P is the power in watts, and V is the voltage in volts. In this case, you would plug in the values of 12W for P and 9V for V to get a charge of 1.33 coulombs.

2. What is the unit of measurement for charge?

The unit of measurement for charge is coulombs (C). One coulomb is equal to the amount of charge carried by a current of one ampere in one second.

3. How does voltage affect the charge in a circuit?

Voltage is directly proportional to the charge in a circuit. This means that as the voltage increases, so does the charge. In other words, the higher the voltage, the more charge is present in the circuit.

4. Can I calculate the charge in a 9V, 12W radio using a different formula?

Yes, there are other formulas that can be used to calculate charge, such as Q = I * t, where Q is the charge in coulombs, I is the current in amperes, and t is the time in seconds. However, for a simple circuit like a radio, using the formula Q = P/V is the most efficient method.

5. What is the difference between charge and current?

Charge and current are related but different concepts. Charge refers to the amount of electric charge present in a circuit, while current refers to the rate at which that charge is flowing. In other words, charge is a measure of the quantity of electricity, while current is a measure of the flow of that electricity.

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