Question

A dryer uses 15 A of current at 240 V for 1.2 h. How much will it cost to do the laundry?

Answer 1

Write the data down. This will help you solve the question:

I = 15 A

V = 240 V

t = 1.2 h

The power output of the dryer is:

P = I x V

P = 15 x 240

P = 3,600 W

Convert the time in seconds:

T = 1.2 h x 60 minutes x 60 seconds = 4,320 seconds

The energy cost is:

E = P x T

E = 3,600 x (4,320)

E = 15,552,000 J

Or using scientific notation we get:

$E=1.5552\times10^7J$