Question

Five hundred joules of energy are used to move 100 C of charge through a resistor. What is the voltage of resistor?

Answer 1

Answer:

Given potential difference V = 100volts,

Resistance of the resistor, R = 50ohms.

So power produced in the circuit , P =(V^2)/R

i.e. P = 100*100/50 = 200 watt = 200 J/s.

But we know, P = energy/ time

So, energy = power * time

Time should be taken in it's standard units i.e seconds

6min 58 seconds = (6*60)+58 = 418 seconds.

Energy = (200 *418)J = 83,600J

We know that 1calorie = 4.184J

So, energy= (83,600)/4.184 = 19,980.87 calories.

Final answer :-(1) energy = 83,600 J

(2) energy = 19,980.87 calories.

Answer 2

Given: Energy used= 500J, charge through resistor = 100C

To find: Voltage across the resistor

Solution: We know that voltage is a difference of potentials between points of an electric circuit.

Also, potential or voltage is the amount of potential energy required to let a point of unit positive charge sit still inside an electric feisty.

Therefore we can also say that energy needed to move a charge Q from one point to another having potential difference or voltage is

E= Q×Vab

in which E us the energy required, Q js charge pf the particle, Vab is the potential difference between two points where the charge Q will be moved.

Here in the question, we are given Q and energy we can find voltage

V= E/Q= 500/100= 5V

Therefore voltage of the resistor will be 5V.