Advertisements
Advertisements
प्रश्न
Write scientific reason.
A coil made up of alloy Nichrome is used in the electric heater cooker as a resistor.
Advertisements
उत्तर
- The electric heater-cooker works on the principle of heating effect of electric current.
- Alloys (such as nichrome) as compared to metals have higher resistivity.
- Unlike metals they can be heated to higher temperature.
Hence, a coil made up of alloy nichrome is used in the electric heater-cooker as a resistor.
APPEARS IN
संबंधित प्रश्न
State four most common electrical appliances based on heating effect of electric current. Why do we use finely heated platinum wire in surgery?
An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.
Why are the coils of electric irons and electric toasters made of an alloy rather than a pure metal?
Why is a series arrangement not used for connecting domestic electrical appliances in a circuit?
Write down the formula for the heat produced when a current I is passed through a resistor R for time t.
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
Which of the following characteristic is not suitable for a fuse wire?
(a) thin and short
(b) thick and short
(c) low melting point
(d) higher resistance than rest of wiring
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?
An electric iron of 1100 W is operated for 2 hrs daily. What will be the electrical consumption expenses for that in the month of April? (The electric company charges Rs 5 per unit of energy).
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.
In an electric bulb, coil of _______ metal is used.
Which of the following substance contracts on heating?
Write two devices based on the heating effect of electric current.
Name any two appliances which works on the phenomenon of heating effect of electric current.
Explain the importance/uses of fuse wire.
How can overloading be avoided?
Explain the application of heating effect of electric current in an electric bulb with a diagram.
Define fuse.
Which of the following is correct?
A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross-section of the filament in 16 seconds would be roughly:
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?
An electric cell produces electricity from the ______ ______ in it.
Can we use the same fuse in a geyser and a television set? Explain.
An MCB can be used instead of a fuse in an electrical circuit.
An electric fuse has a body made of ceramic and two points for connecting the fuse wire.
What is an electric fuse made up of?
Fuse is a strip of alloy wire which is made up of lead and tin with a very low ______.
A trip switch is a ______ safety device.
The electric fuse works on the Joule heating principle.
1 kWh is equal to ______.
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?
Write an expression for the amount of heat produced in a resistor when an electric current is passed through it stating the meanings of the symbols used.
Anannya responded to the question: Why do electrical appliances with metallic bodies are connected to the mains through a three-pin plug, whereas an electric bulb can be connected with a two-pin plug?
She wrote: Three-pin connections reduce heating of connecting wires.
- Is her answer correct or incorrect? Justify.
- What is the function of a fuse in a domestic circuit?
An electric iron of resistance 20 Ω draws a current of 5 A. The heat developed in the iron in 30 seconds is ______.
An electric iron is rated 220 V, 2 kW. If the iron is used for 3h daily find the cost of running it for one week if it costs ₹ 4.25 per kWh.
