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प्रश्न
What is Joule’s heating effect? How can it be demonstrated experimentally? List its four applications in daily life.
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उत्तर
Joule's law of heating states that heat produced in the resistor is
- directly proportional to the square of the current.
- directly proportional to the resistance.
- directly proportional to the current.
Mathematically,
H = i2Rt
where,
H = Heat produced
I = Current
R = Resistance
t = time
Experimental demonstration
- Take a water heating immersion rod, water, bucket, thermometer, regulator.
- Immerse the water heating immersion rod in the water and measure the time taken to heat the water upto a certain temperature.
- Now increase the current to double with the help of regulator and now measure the time taken to heat the water upto the same temperature.
Then, we will observe that time taken in second case will be one fourth the time taken in earlier case. Hence, it verifies the Joule's law of heating.
Electric fuse, toaster, oven, kettle, are the four applications of Joule's law of heating in daily life.
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संबंधित प्रश्न
The safety device based on the heating effect of electric current is called a ______.
What is nichrome? State its one use.
A heating coil has a resistance of 200 Ω. At what rate will heat be produced in it when a current of 2.5 A flows through it?
The current passing through a room heater has been halved. What will happen to the heat produced by it?
The elements of electrical heating devices are usually made of:
(a) tungsten
(b) bronze
(c) nichrome
(d) argon
Identify the figure and give its use.
Statement 1 : Electric current ( flow of electrons ) creates heat in the resistor.
Statement 2 : Heat in the resistor is created according to the rule of energy conservation.
Explain Statement 1 with the help of Statement 2.
Give scientific reason :
In the electric equipment producing heat e.g. iron, electric heater, boiler, toaster, etc., an alloy such as Nichrome is used, not pure metals.
Name any six domestic appliances based on the heating effect of electric current.
Solve the following question.
Compute the heat generated while transferring 96000 coulombs of charge in two hours through a potential difference of 40 V.
These days when current in the circuit suddenly increases _______ switches are used.
Name any two appliances which works on the phenomenon of heating effect of electric current.
When does overloading occur?
Mark the correct choice
- Assertion: Electric appliances with a metallic body have three wire connections.
- Reason: Three-pin connections reduce the heating of the connecting wires.
Assertion: Bending of wire decreases the resistance of the electric wire.
Reason: The resistance of a conductor depends on length, thickness, nature of material and temperature of the conductor.
An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?
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.
An electric fuse has a body made of ceramic and two points for connecting the fuse wire.
In the electric equipment producing heat like iron, electric heater, boiler, toaster etc., an alloy such as nichrome is used, not pure metals.
