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Question
An electric iron of power 1.5 kW is used for 30 minutes to press the clothes. Calculate the electrical energy consumed in
- kilowatt-hour
- joule.
Solution
(a) Given: P = 1.5 kW; t = 30 minutes = `30/60 = 1/2`hr
∴ P = `w/t`
∴ W = P × t
∴ 1.5 × `1/2`
= 0.75 kwh
(b) 1 kWh = 3.6 × 106 J
∴ 75 kWh = 0.75 × 3.6 × 106
= 2.700 × 106
= 2.7 × 106 J
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