Question

The image given below displays kilowatt-hour meter readings recorded at two distinct points in time.

Assuming a continuously running 2000 W air conditioner as the sole electrical device in use, calculate the time interval, in hours, between these two meter readings.

Answer 1

Given: Power rating of air conditioner (P) = 2000 W

Initial meter reading = 856 KWh = 856 × 1000 Wh = 856000 Wh

Final meter reading = 1567 KWh = 1567 × 1000 Wh = 1567000 Wh

Now,

Total electrical energy consumed (E) = Final meter reading − Initial meter reading

= 1567000 − 856000

= 711000 Wh

Then,

Total time interval = `E/P`

= `(711000)/(2000)`

= `711/2`

= 355.5 hours

So, the air conditioner is running for 355.5 hours.