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  1. Class 9
  2. Chapter 11 Class 9 - Work and Energy

Transcript

NCERT Question 20 Find the energy in kWh consumed in 10 hours by four devices of power 500 W each. Power of 1 device = 500 W Power of 4 devices = 4 Γ— 500 W = 2000 W Time taken = 10 hours We know that Power = (πΈπ‘›π‘’π‘Ÿπ‘”π‘¦ π‘π‘œπ‘›π‘ π‘’π‘šπ‘’π‘‘)/(π‘‡π‘–π‘šπ‘’ π‘‘π‘Žπ‘˜π‘’π‘›) Energy consumed = Power Γ— Time taken = 2000 Γ— 10 = 20000 Wh = 20000/1000 kWh = 20 kWh Energy consumed is 20 kWh

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Davneet Singh's photo - Teacher, Computer Engineer, Marketer
Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.