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प्रश्न
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उत्तर
Electrical power is defined as the rate at which energy is changed or work is done i.e., the work done per second or energy converted per second.
Electrical appliances come with certain number of watts and volts written on them. Power rating of an electrical appliance gives the knowledge of the safe current limit of an appliance and also indicates the voltage above which the appliance should not be used.
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संबंधित प्रश्न
Define watt. Write down an equation linking watts, volts and amperes.
Why is an electric light bulb not filled with air? Explain why argon or nitrogen is filled in an electric bulb.
Electrical power p is given by the expression P = (Q × V) ÷ time. Express the power P in terms of current and resistance explaining the meaning of symbols used there in.
An electric bulb is marked 100 W, 230 V. What does this mean?
What do you understand by ‘earthing’? What are the advantages of earthing in a household electric circuit? Explain, how it is done?
Find the heat produced in joules when a current of 10 amperes flows through a connecting wire of resistance 2 × 10-2 ohms and heating element of resistance 250 ohms for 2 seconds.
An Electric bulb is marked 100 W, 230 V. What how long would this lamp take to consume one unit of electricity?
An electrical appliance is rated 1500 W, 250 V. This appliance is connected to 250 V mains. Calculate:
(i) the current drawn,
(ii) the electrical energy consumed in 60 hours,
(iii) the cost of electrical energy consumed at Rs. 2.50 per kWh.
A torch bulb is rated at 3 V and 600 mA. Calculate it’s
- power
- resistance
- energy consumed if it is used for 4 hours.
An overhead tank of capacity 10 k litre is kept at the top of building 15 m high. Water falls in tank with speed 5`sqrt2` m/s. Water level is at a depth 5 m below ground. The tank is to be filled in `1/2` hr. If efficiency of pump is 67.5% electric power used is ______ W.
