sci_phy
Electrical Power and Energy
Chapter summary, hard words and model exam answers for ICSE Class 10 Hindi.
Free online summary and notes (ICSE Class 10 Hindi). Read it here, no PDF download needed.
About the author
Physics · CBSE 10 · ICSE 10 · GCSE (AQA, Edexcel, OCR)
Summary
A 230 V kettle drawing 9 A has power 230 × 9 ≈ 2070 W, so it delivers about 2070 J every second.
Pick the form that uses the quantities you are given. All three give the same answer.
A 100 W bulb on for 600 s transfers 100 × 600 = 60 000 J.
1 kWh = 3.6 × 10⁶ J. A 2 kW AC for 8 h uses 16 units; at ₹6 that costs ₹96.
Hard words & meanings
| power | the rate at which energy is transferred, P = V×I, measured in watts |
| watt (W) | the SI unit of power; one watt is one joule per second |
| energy | the total amount transferred, E = P×t, measured in joules |
| joule (J) | the SI unit of energy |
| kilowatt-hour (kWh) | a unit of energy equal to 3.6 × 10⁶ J; the 'unit' on a bill |
| power rating | the power an appliance uses in normal use, marked in watts |
| efficiency | the fraction of input energy that becomes useful output |
| fuse | a safety device that melts and breaks the circuit if current gets too high |
Model exam answers, grammar & audio
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