Calculating Charge in a 9V, 12W Radio

  • Thread starter Thread starter aaronmilk3
  • Start date Start date
  • Tags Tags
    Charge Radio
Click For Summary
To calculate the charge passing through a 9V, 12W radio over 1.33 hours, the correct approach involves determining the current using the formula P = IV, leading to I = P/V, which gives 1.33A. The total time in seconds is 4,788 seconds. The charge can then be calculated using Q = It, resulting in Q = 1.33A * 4,788s, which equals approximately 6,367 coulombs. The initial miscalculations stemmed from incorrect resistance and power equations. Ultimately, the correct charge calculation resolves the confusion.
aaronmilk3
Messages
12
Reaction score
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!
 
Physics news on Phys.org
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.
 
Never mind I figured out
 

Thread 'Magnitude of buoyant force in fluids of different densities'

The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?
View full post »

Similar threads

Current and resistance of wire heating up water
  • · Replies 4 ·
Replies
4
Views
4K
Charge on Capacitor in RLC Circuit
  • · Replies 5 ·
Replies
5
Views
5K
Concentric Wire Homework: Calculating Potential, Capacitance, Charge & Energy
  • · Replies 2 ·
Replies
2
Views
2K
Calculating Tension and Charge Magnitude in Charged Particle Systems
  • · Replies 2 ·
Replies
2
Views
5K
Calculating Charge and Current
  • · Replies 13 ·
Replies
13
Views
6K
Calculating Charge Using Coulomb's Law
  • · Replies 6 ·
Replies
6
Views
3K
Calculate Coulombs Law: Charge, Current, and Power in Electrical Circuits
  • · Replies 4 ·
Replies
4
Views
2K
Basic RC Circuit Homework: Calculate Time Constant & Charge Decay
  • · Replies 3 ·
Replies
3
Views
2K
How Do You Calculate the Current in Each Wire When a Charge Moves Between Them?
  • · Replies 4 ·
Replies
4
Views
2K
Charge through a coil in a magnetic field
  • · Replies 6 ·
Replies
6
Views
6K