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An electric heater takes 1.2kwh in 30min at 120V having an efficiency of 99%.The heat energy required boil a certain amount of water is 99KJ.If the current taken by heater is 20 amp at 120V.Find the time required to boil water?

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Answer:

Explanation:

Power of the heater = P watt .

P x .5 = 1200

P = 2400 W

If resistance of heater R

V² / R = 2400

120²/ R = 2400

R = 6 ohm .

heat to be produced = 99000 J

Current be I

I²R t  x .99 = 99000

20² x 6 x t x .99 = 99000

t = 41.67 s

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