Question

For a heater rated at 4 kW and 220 V, calculate:; (a) the current,; (b) the resistance of the heater,; (c) the energy consumed in 2 hours, and; (d) the cost if 1 kWh is priced at ₹ 4.60

Answer 1

Answer:

I = 18.18 A   & R = 12.1 ohm &  8 KWh and 36.8 ₹

ExplIanation:

P = V I                    ║    P = V²/ R ⇒R =  V²/ P

I = P / V                  ║    R = (220)²/ 4000

I =  4000 / 220      ║    R = 12.1 ohm

I = 18.18 A             ║

energy consumed in KWh = watt × time in hours /1000

energy consumed in KWh = 4000×2/1000

                                            =  8 KWh

cost of electricity = 8 × 4.60  

                             = 36.8 ₹

Answer 2

Answer:

P = V I                       P = V²/ R ⇒R =  V²/ P

I = P / V                     R = (220)²/ 4000

I =  4000 / 220         R = 12.1 ohm

I = 18.18 A            

energy consumed in KWh = watt × time in hours /1000

energy consumed in KWh = 4000×2/1000

                                           =  8 KWh

cost of electricity = 8 × 4.60  

                            = 36.8 ₹

Explanation: