LESSON – POWER & ENERGY

WORK EXAMPLE – POWER & ENERGY

EXAMPLE

A single resistor of 200 ohms has 0.05 amps of current going through it. Calculate the power consumption of the resistor. Calculate the amount of energy it uses after 5 hours.

SOLUTION

Step 1 – Calculate voltage drop.

V = I x R

= 0.05 x 200

= 10 volts

Step 2 – Calculate the power over the resistor.

P = V x I

= 10 x 0.05

= 0.5 watts

Step 3 – Calculate the energy used after 5 hours.

E = P x t

= 0.5 x 5

= 2.5 watt hours