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संबंधित प्रश्न
What determines the rate at which energy is delivered by a current?
Define watt. Write down an equation linking watts, volts and amperes.
An electric motor takes 5 amperes current form a 220 volt supply line. Calculate the power of the motor and electric energy consumed by it in 2 hours.
Calculate the current through a 60 W lamp rated for 250 V. If the line voltage falls to 200 V, how is the power consumed by the bulb affected?
An electric bulb is rated at 220 V, 100 W. (a) what is its resistance? (b) what safe current can be passed through it?
What is the resistance, under normal working conditions of a 240 V electric lamp rated at 60 W? If two such lamps are connected in series across a 240 V mains supply, explain why each one appears less bright.
A coil of copper wire is connected to a galvanometer. What would happen if a bar magnet is:
(i) Pushed into the coil with its north pole entering first?
(ii) Held at rest inside the coil?
(iii) Pulled out again?
Why is the heating element of an electric oven wound on a helix? State the reason.
A student wants to use an electric heater, an electric bulb and an electric fan simultaneously.
How should these gadgets be connected with the mains? Justify your answer giving three reasons.
