Distinguish between kilowatt and kilowatt hour. For a heater rated at 4.4 kW; 220 Y calculate the (i) current drawn by the heater. (ii) resistance of the heater element. (iii) energy consumed by the heater in 5 hours. (iv) cost of running the heater if 1 kW h costs ₹ 6’50’

Distinction between kilowatt and kilowatt hour:
kilowatt:- 1. It is a unit of electrical Power.
2. Power in kW = V(volt) x l(ampere)/1000
kilowatt hour:- 1. It is a unit of electrical energy.
2. Energy in kw h = v(volt)x l(ampere) x t(hour)/1000
As the heater is rated 4’4kW;220 V, hence
(i) Current drawn by the heater t = P/V = 4.4KW/220V = 4.4 x 1000W /220V = 20A
(ii) Resistance of the heater element R = V/I = 220V/20A = 11Ω
(iii) Energy consumed by the heater in 5 hours E =Pt = 4.4 kW x 5 h = 22 kw h
(iv) Cost of running the heater @ ₹ 6.50 per kw h=22 x ₹ 6.50 = ₹ 143