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Electric Energy: Consumption and Conservation
Physics · Kerala SSLC (Class 10) · English Medium · 36 questions and answers
Sample questions
- Q: Define electric power.
- A: Electric power is the rate at which electrical energy is consumed or converted into other forms. It is the energy used per unit time.
- Q: Write the formula for electric power and its SI unit.
- A: Electric power P = VI = I²R = V²/R, where V is voltage, I is current and R is resistance. Its SI unit is the watt (W).
- Q: What is 1 watt?
- A: One watt is the power consumed when a current of 1 ampere flows through a device across a potential difference of 1 volt (1 W = 1 V × 1 A).
- Q: How is electrical energy calculated?
- A: Electrical energy = power × time, that is E = P × t. If power is in watts and time in seconds, energy is in joules.
- Q: What is the commercial unit of electrical energy?
- A: The commercial unit of electrical energy is the kilowatt-hour (kWh), also called one unit. 1 kWh = 1 unit.
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