Electrical Power and Energy
Physics ⇒ Electricity and Magnetism
Electrical Power and Energy starts at 8 and continues till grade 12.
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See sample questions for grade 9
A 100 W lamp is switched on for 3 hours. How much energy does it use in Joules?
A 1200 W microwave oven is used for 10 minutes. How much energy does it use in kWh?
A 1500 W geyser is used for 20 minutes. Calculate the energy consumed in kWh.
A 200 W computer is used for 5 hours. How much energy does it consume in kWh?
A 240 V electric kettle draws 5 A of current. What is its power rating?
A 40 W lamp is used for 12 hours. How much energy does it consume in kWh?
A 500 W refrigerator runs for 24 hours. How much energy does it consume in kWh?
A 60 W bulb is used for 5 hours. How much energy does it consume in Joules?
A 60 W bulb operates at 120 V. What is the current through the bulb?
A heater is rated 2000 W, 220 V. What current does it draw?
Explain the difference between power and energy in the context of electricity.
Explain why a 100 W bulb glows brighter than a 60 W bulb when both are connected to the same voltage supply.
Explain why electrical energy is often measured in kilowatt-hours instead of joules for household consumption.
If a 50 W device is used for 10 hours, how much energy does it consume in Joules?
If a 75 W fan runs for 8 hours a day for 30 days, how much energy does it consume in kWh?
If a device uses 500 W of power for 2 hours, how much energy does it consume in kilowatt-hours (kWh)?
If the voltage across a 10 Ω resistor is 20 V, what is the power dissipated?
What is the formula for electrical power in terms of voltage and current?
A 120 V toaster draws a current of 4 A. Calculate the energy consumed in 15 minutes in joules.
A 60 W bulb and a 100 W bulb are connected in parallel to a 220 V supply. Which bulb will consume more energy in 5 hours, and by how much (in kWh)?
