Question

what are the commercial unit of electrical energy ?which uses more energy - a 250 w TV set in 1 hour 1200 w electric iron in 10 minutes an how

Answer 1

The commercial unit of electrical energy is "units" or "kW hr"

for TV

power, p = 250 W = 250/1000 kW = 1/4 kW

usage time, t = 1 hr

Electric energy drawn, e

e = pt

e = (1/4)(1)

e = 0.25 kW hr = 0.25 unit

for electric iron

power, P = 1200 W = 1200/1000 kW = 1.2 kW

usage time, T = 10 minutes = 10/60 hr = 1/6 hr

Electric energy drawn, E

E = PT

E = (1.2)(1/6)

E = (0.2)(1)

E = 0.2 kW hr = 0.2 unit

since 0.25 > 0.2

hence, e > E

hence, the TV uses more energy

Answer 2

Answer:

the commerical unit of power=250w