Question

In doing a load of clothes, a clothes dryer uses 16 A of current at 240 V for 45 min. A personal computer, in contrast, uses 2.7 A of current at 120 V. With the energy used by the clothes dryer, (a) How long (in hours) could you use this computer to surf the Internet? (b)At $0.12 per kilowatt-hour, how much does it cost to operate the clothes dryer for 45 minutes?

Answer 1

Answer:

(a) Total time will be 8.05 hour

(B) Total cost will be $417.6                

Explanation:

We have given dryer uses 16 A of current so current i = 16 A

Voltage V = 240 volt

Time t = 45 minutes =45×60 = 2700 sec

So power P = VI = 240×16 = 3840 W

So energy E = power×time = 3840×45×60 = 9396 KJ

(A) Now current in the computer i = 2.7 A

Voltage V = 120 V

So power P = 120×2.7 = 324 W

Now computer is using energy of dryer

So time by which it will use energy is $t=\frac{9396000}{324}=29000sec=8.05hour$

So time will be 8.05 hour

(b) Cost per kilowatt is $0.12

So total cost =3480×0.12 = $417.6