100000W of power is delivered to the other side of a city by a pair of power lines with the voltage difference of 15000V.
a) how much current flows in the lines?
100000/15000 = 6.9 A
b) Each of the 2 lines has a resistance of 10 ohms. What is the voltage change along each line?
6.9 x 10 = 69
c)How much power is wasted as heat in both lines together?
how on earth do you do part c ? help would be appreciated. thanks!
You punched a wrong button somewhere for 100,000/15,000. I have 6.67.
That slight difference will change answer b a little.
c. Power = I2R
Where I is current in amperes and R is resistance in ohms.
Thank you!
RIGHT, well this might be a bit late but i'm another physics student and just found the solution.
Basically you want to take your current from part A - and your resistance from part B, plug them in into the equation P = I^2R and then subtract your answer from the original power. i.e. 100kwatts
scratch that - no subtraction. just your answer as it is i think
i meant to say voltage and use the equation P = IV - then multiply by 2 since it's both lines KBAI
You're welcome! Let's now calculate the power wasted as heat in both lines together, as requested in part c.
To find the power wasted as heat in each line, we can use the formula P = I^2 * R.
Given that the resistance (R) of each line is 10 ohms, and the current (I) in each line is 6.67A (as you calculated), we can plug these values into the formula:
Power wasted in each line = (6.67A)^2 * 10 ohms
Power wasted in each line = 44.55W
Since there are two lines, we need to multiply the power wasted in each line by 2 to find the total power wasted as heat in both lines together:
Total power wasted as heat = 2 * 44.55W
Total power wasted as heat = 89.1W
Therefore, the power wasted as heat in both lines together is 89.1W.
I hope this helps! Let me know if you have any other questions.