Question

A computer monitor uses 2.0 a of current when it is plugged into a 120 v outlet. the monitor is never turned off. what is the yearly cost of operating the monitor if the cost of electricity is $0.12/kwh

Answer 1

Power (P) is calculated by multiplying current (I) and voltage (V). This can be mathematically expressed as,

P = I x V

P = (2.0 A) x (120 V)
= 240 W

Converting 1 year to number of hours,
1 year x (365 days/1 year) x (24 hr / 1 day)
= 8760 hours

Calculating for the cost of power,

Cost = (240 W) x (1 kW/1000 W) x ($0.12/kWh) x (8460 hours)
Cost = $203.04

Thus, the yearly cost of power is approximately $203.04.