2 kWh = ?
A. 7.2 × 108J
B. 7.2 × 106J
C. 7.2 × 105J
D. 72 × 106J
Answer: Option B
Solution (By Examveda Team)
A kilowatt-hour (kWh) is a unit of energy. It is the amount of energy consumed when a power of 1 kilowatt (1000 watts) is used for 1 hour (3600 seconds).1 kWh = 1000 W × 3600 s = 3.6 × 106 J
Therefore,
2 kWh = 2 × 3.6 × 106 J = 7.2 × 106 J
Hence, 2 kWh = 7.2 × 106 joules, so the correct answer is Option B.
This Question Belongs to Physics GK Chapter Wise >> Unit And Measurement
D is also correct na?
1watt = 1 joule/sec
1kilowatt = 1000 joule/sec
1 hrs = 3600 sec
1kilowatt hours = 1000*3600 joule
1kwh = 3600000 joule.
hence
2kwh = 2*3600000 joule
2kwh = 7200000 joule
or 72* 105 joule
then why option 4 is wrong...
1 hr = 3600 seconds, 1 Kilo watt = 1000 Watt
So, 2 kWh = 3600000 × 2 = 7200000 Joule = 7.2 × 106 J.