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प्रश्न
Explain the application of heating effect of electric current in an electric bulb with a diagram.
उत्तर
- Electric bulb works on the principle of heating effect electric of current.
- The solenoid type coil of bulb has high resistivity and very high melting point.
- When current is passed through the bulb, solenoid type coil of bulb gets heated to high temperature (upto 3400 °C) and starts glowing.
संबंधित प्रश्न
An electric iron of resistance 20 Ω takes a current of 5 A. Calculate the heat developed in 30 s.
Why is the tungsten used almost exclusively for filament of electric lamps?
Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?
Write Joule's law of heating.
An electric heater is connected to the 230 V mains supply. A current of 8 A flows through the heater.
(b) How much energy is transferred to the heater each second?
What is nichrome? State its one use.
Give two reasons why nichrome alloy is used for making the heating elements of electrical appliances.
Why is a series arrangement not used for connecting domestic electrical appliances in a circuit?
Why does the connecting cord of an electric heater not glow hot while the heating element does?
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?
A resistance of 25 Ω is connected to a 12 V battery. Calculate the heat energy in joules generated per minute.
What is meant by the heating effect of current? Give two applications of the heating effect of current.
An electric fuse works on the:
(a) chemical effect of current
(b) magnetic effect of current
(c) lighting effect of current
(d) heating effect of current
Give a scientific reason.
Tungsten metal is used to make a solenoid type coil in an electric bulb.
Solve the following example.
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?
Name the factors on which the heat produced in a wire depends when current is passed in it, and state how does it depend on the factors stated by you.
Find the odd one out and give its explanation.
What is overloading?
Live wire and neutral wires have a 220 V potential difference.
Name some devices that run using heat effect of electric current
Explain the heating effect of electric current.
Heating effect of current is called ______
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.
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?
An electric cell produces electricity from the __________ ___________ in it.
Your teacher has shown you the following activity.
Activity: The teacher has wound a long insulated piece of wire around an iron nail in the form of a coil. The free ends of the wire are connected to a cell through a switch as shown in Figure 14.3. The current is switched on and some pins are placed near the ends of the nail.
Write down any three questions that come to your mind about this activity
An MCB can be used instead of a fuse in an electrical circuit.
Fuse is a strip of alloy wire which is made up of lead and tin with a very low ______.
An electric fuse is a wire made up of a material having ______ melting point.
A trip switch is a ______ safety device.
A fuse is used in an electric circuit to stop high currents flowing through the circuit.
Find the odd one out.
When a current I flows through a wire of resistance R for time t then the electrical energy produced is given by ______.
An electric iron of resistance 20 Ω draws a current of 5 A. The heat developed in the iron in 30 seconds is ______.
