CBSE Class 10 Answered

P = V²/R

Hence, R₁ = 220x220/500 Ωand R₂ = 220x220/800 Ω

1/ Since they are connected in parallel,

Current drawn by 500 W heater = V/R₁ = 220/(220x220/500) = 25/11 A

Current drawn by 800 W heater = V/R₂ = 220/(220x220/800) = 40/11 A

2/Resistance of 500W heater = 220x220/500 = 484/5 Ω

Resistance of 800W heater = 220x220/800 = 121/2 Ω

3/ Electric energy consumed if they operate for 2 hrs.

500 W heater will consume, (0.5kW)(2hr) = 1kWhr.

800 W heater will consume, (0.8kW)(2hr) = 1.6kWhr

Total electric energy consumed = 1 + 1.6 = 2.6 kWhr.

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