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प्रश्न
In the electric equipment producing heat like iron, electric heater, boiler, toaster etc., an alloy such as nichrome is used, not pure metals.
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उत्तर
The performance and life of a heating element are determined by the material used to make the heating element. The heating element material must have a high melting point, high tensile strength, high resistivity, and a low-temperature coefficient of resistance. Because an alloy's resistivity is greater than that of pure metal, alloys are employed in electrical heating devices rather than pure metals. Furthermore, even at greater temperatures, the alloy does not easily burn (or oxidise).
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संबंधित प्रश्न
Why does the cord of an electric heater not glow while the heating element does?
Compute the heat generated while transferring 96000 coulomb of charge in one hour through a potential difference of 50 V.
Name any two effects of electric current.
An electric room heater draws a current of 2.4 A from the 120 V supply line. What current will this room heater draw when connected to 240 V supply line?
Why are the coils of electric irons and electric toasters made of an alloy rather than a pure metal?
Why does the connecting cord of an electric heater not glow hot while the heating element does?
Name the material which is used for making the filaments of an electric bulb.
If the current flowing through a fixed resistor is halved, the heat produced in it will become:
Which electric heating device in your home do you think have resistors which control the flow of electricity?
Three heaters each rated 250 W, 100 V are connected in parallel to a 100 V supply. Calculate:
- the total current taken from the supply
- the resistance of each heater and
- the energy supplied in kWh to the three heaters in 5 hours.
Heat energy is being produced in a resistance in a circuit at the rate of 100 W. The current of 3 A is flowing in the circuit. What must be the value of the resistance?
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Answer the following question:
what is the heating effect of the electric current? state any four applications of it?
Compute the heat generated while transferring 96000 coulombs of charge in two hours through a potential difference of 40 V.
Explain the importance/uses of fuse wire.
Name some devices that run using heat effect of electric current
Which of the following is correct?
An electric iron consumes energy at the rate of 420 W when heating is at the maximum rate and 180 W when heating is at the minimum rate. The applied voltage is 220 V. What is the current in each case?
Why is parallel arrangement used in domestic wiring?
B1, B2 and B3 are three identical bulbs connected as shown in Figure. When all the three bulbs glow, a current of 3A is recorded by the ammeter A.
- What happens to the glow of the other two bulbs when the bulb B1 gets fused?
- What happens to the reading of A1, A2, A3 and A when the bulb B2 gets fused?
- How much power is dissipated in the circuit when all the three bulbs glow together?
Three incandescent bulbs of 100 W each are connected in series in an electric circuit. In another circuit another set of three bulbs of the same wattage are connected in parallel to the same source.
- Will the bulb in the two circuits glow with the same brightness? Justify your answer.
- Now let one bulb in both the circuits get fused. Will the rest of the bulbs continue to glow in each circuit? Give reason.
(a) Observe the diagram given below and state whether the bulb will glow or not when we switch on K.
(b) Is it safe to handle the bulb when the switch is OFF?
(c) Give a reason for your answer in (b).
Name two electric devices for each where
- heating effect of current is used and
- magnetic effect of current is used.
An electric fuse has a body made of ceramic and two points for connecting the fuse wire.
What are the uses of electromagnets?
What are the factors affecting heating effect of electric current?
Copper wire offers very little ______ and does not get heated up quickly.
Name a few appliances which work on the basis of the heating effect of current.
An electrochemical cell converts ______ energy into ______ energy.
A fuse is used in an electric circuit to stop high currents flowing through the circuit.
Explain why fuse wire is always connected in a series arrangement.
In which of the following applications of Iron, rusting will occur most? Support your answer with valid reason.
| A | B | C | D |
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State the law that explains the heating effect of current with respect to the measurable properties in an electrical circuit.
