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प्रश्न
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उत्तर
Electrical energy is defined as the total amount of work done to maintain current in a circuit in a given time. Its SI unit is joule.
The rate at which electrical energy is consumed per unit time is called electrical power. It is denoted by P. i.e., Its SI unit is watt.
Electrical power = `"Electrical energy"/"time"`
The other name of kWh is Board of Trade Unit (BOTU).
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संबंधित प्रश्न
Define watt-hour. How many joules are equal to 1 watt-hour?
An electric bulb is connected to a 220 V power supply line. If the bulb draws a current of 0.5 A, calculate the power of the bulb.
A bulb is rated as 250 V; 0.4 A. Find its : (i) power, and (ii) resistance.
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.
Water in an electric kettle connected to a 220 V supply took 5 minutes to reach its boiling point. How long would it have taken if the supply voltage had fallen to 200 V?
A bulb with rating 250 V, 100 W is connected to a power supply of 220 V situated 10 m away using a copper wire of area of cross-section 5 mm2. How much power will be consumed by the connecting wires? Resistivity of copper = 1.7 × 10−8 Ωm
An electric current is passed through a metallic wire. The wire gets heated up. Give the reason. Is it possible to melt the wire by passing a heavy current?
An electric heater is rated 220 V, 550 W. What does this statement mean?
Two bulbs are rated: bulb A 100W, 120 V bulb B 10 W, 120 V. If both are connected across a 120V supply, which bulb will consume more energy, When in parallel? Also calculate the current through each bulb in the above cases.
1 kWh = ______ J.
