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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
Name the S.I unit of electrical energy. How is it related to Wh?
An electrical appliance having a resistance of 200Ω is operated at 200 V. Calculate the energy consumed by the appliance in 5 minutes (i) in joules (ii) in kWh.
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
The diagram above shows a circuit with the key k open. Calculate :
(i) the resistance of the circuit when the key k is open.
(ii) the current drawn from the cell when the key k is open.
(iii) the resistance of the circuit when the key k is closed.
(iv) the current drawn from the cell when the key k is closed.
Why is heating coil wound in the form of a helix in electric stove?
An electric filament lamp is connected to a supply of voltage higher than the recommended value. Give reasons, why compared with a normal performance, the lamp emits a brighter light and its life is shortened.
‘The current rating of a fuse is 5A’. Comment on this statement.
With reference to the diagram shown below calculate:
(i) The equivalent resistance between P and Q.
(ii) The reading of ammeter.
(iii) The electrical power between P and Q.
An electric lamp A of 40 W and another electric lamp B of 100 W are connected to 220 V supply. Calculate the ratio of their filament resistances?
