Posted by Belle on Tuesday, January 30, 2007 at 8:57pm.
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 = I
^{2}R
Where I is current in amperes and R is resistance in ohms.
Thank you!

Physics  Nick, Wednesday, April 3, 2013 at 7:28pm
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

Physics  Nick, Wednesday, April 3, 2013 at 7:30pm
scratch that  no subtraction. just your answer as it is i think

Physics  Nick, Wednesday, April 3, 2013 at 7:35pm
i meant to say voltage and use the equation P = IV  then multiply by 2 since it's both lines KBAI
Answer This Question
Related Questions
 science  A power of 200 kW is delivered by power lines with 48,000 V difference...
 Physics  Power transmission lines often use a form of electric current called ...
 Physics  A neighbourhood requires 1.5 x 10^5 w of electricity to power all ...
 physics  An electrical power plant generates electricity with a current of 50A ...
 calculus  A power station is on one side of a river that is 0.5 mile wide, and ...
 physics  1. xray machine operates at 200 kv with a current of 10 mA. The power...
 Transformers  Two 6600/ 250 V transformers have the following short circuited ...
 help  If you know the power rating of an appliance and the voltage of the line ...
 physics  In periods of peak demand, power companies lower their voltage. This ...
 physics  In periods of peak demand, power companies lower their voltage. This ...
More Related Questions