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

Transcript

Example 11.9 An electric bulb of 60 W is used for 6 h per day. Calculate the β€˜units’ of energy consumed in one day by the bulb. Power of bulb = 60 W Time taken = t = 6 h 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 = 60 Γ— 6 = 360 Wh = 360/1000 kWh = 0.36 kWh 1000 W = 1 kW 1 W = 1/1000 kW We know that 1 kWh = 1 unit 0.36 kWh = 0.36 Γ— 1 = 0.36 units ∴ Energy consumed by bulb is 0.36 units

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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.