Question

An electric appliance is rated at 1000KVA,220V.If the appliance is operated for 2hrs.Calculate:

(i)kWh

(ii)joule

Answer 1

(1) the following relation exists

Power in kW = Power in KVA x Power Factor

here we can assume the power factor to be 1.

so,

Power in kW = Power in KVA

thus

1000 KVA = 1000 kW

or in KWh

1000 KVA = 1000 KW x 2 hours

so,

1000KVA = 2000 KWh

(2)

now,

1 KWh = 3.6 x 10⁶ J

thus

2000 KWh = 2000 x 3.6 x 10⁶ J

thus,

2000 KWh = 7.2 x 10⁹ J

KVA is short for kilovolt-ampere and is a commonly used unit for power.