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प्रश्न
Write two devices based on the heating effect of electric current.
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उत्तर
Fuse wire, electric iron, electric bulb, electric cooker, geyser.
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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.
An electric iron of resistance 20 Ω takes a current of 5 A. Calculate the heat developed in 30 s.
The safety device based on the heating effect of electric current is called a ______.
Give two reasons why nichrome alloy is used for making the heating elements of electrical appliances.
How does the resistance of a wire vary with its:
diameter?
Why does the connecting cord of an electric heater not glow hot while the heating element does?
Explain why, the current that makes the heater element very hot, only slightly warms the connecting wires leading to the heater.
The electrical resistivities of four materials P, Q, R and S are given below:
| P | `6.84xx10^8`Ωm |
| Q | `1.70xx10^8`Ωm |
| R | ` 1.0xx10^15`Ωm |
| s | `11.0xx10^-7`Ωm |
Which material will you use for making: (a) heating element of electric iron (b) connecting wires of electric iron (c) covering of connecting wires? Give reason for your choice in each case.
An electric iron is connected to the mains power supply of 220 V. When the electric iron is adjusted at 'minimum heating' it consumes a power of 360 W but at 'maximum heating' it takes a power of 840 W. Calculate the current and resistance in each case.
Give a scientific reason:
For electric power transmission, copper or aluminium wire is used.
Give Scientific reason.
In practice, the unit kWh is used for the measurement of electrical energy, rather than joule.
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.
Why does tungsten metal used to make solenoid type coil in an electric bulb?
Solve the following question.
Compute the heat generated while transferring 96000 coulombs of charge in two hours through a potential difference of 40 V.
In an electric bulb, coil of _______ metal is used.
The electricity bill specifies the usage in _______.
These days when current in the circuit suddenly increases _______ switches are used.
Which metal is used to make the filament of an electric bulb?
Write scientific reason.
A coil made up of alloy Nichrome is used in the electric heater cooker as a resistor.
Name any two appliances which works on the phenomenon of heating effect of electric current.
How can overloading be avoided?
Explain the application of heating effect of electric current in an electric bulb with a diagram.
Name some devices that run using heat effect of electric current
Explain the heating effect of electric current.
Name any two appliances which work under the principle of heating effect of current.
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.
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?
The heating element of an electric iron is made up of:
Which of the following gases are filled in electric bulbs?
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?
What is Joule’s heating effect? How can it be demonstrated experimentally? List its four applications in daily life.
Can we use the same fuse in a geyser and a television set? Explain.
Your teacher has shown you the following activity.
Activity: Teacher has wound a long insulated piece of wire around an iron nail in the form of a coil. Free ends of the wire are connected to a cell through a switch as shown in the following figure. 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.
Paheli took a wire of length 10 cm. Boojho took a wire of 5 cm of the same material and thickness. Both of them connected the wires as shown in the circuit given in the following figure. The current flowing in both the circuits is the same.
- Will the heat produced in both cases be equal? Explain.
- Will the heat produced be the same if the wires taken by them are of equal lengths but of different thickness? Explain.
What are the uses of electromagnets?
What is an electric fuse made up of?
Copper wire offers very little ______ and does not get heated up quickly.
Fuse is a strip of alloy wire which is made up of lead and tin with a very low ______.
The following is not a safety device.
A fuse is used in an electric circuit to stop high currents flowing through the circuit.
Find the odd one out.
In the electric equipment producing heat like iron, electric heater, boiler, toaster etc., an alloy such as nichrome is used, not pure metals.
Two students decided to investigate the effect of water and air on iron object under identical experimental conditions. They measured the mass of each object before placing it partially immersed in 10 ml of water. After a few days, the object were removed, dried and their masses were measured. The table shows their results.
| Student | Object | Mass of Object before Rusting in g |
Mass of the coated object in g |
| A | Nail | 3.0 | 3.15 |
| B | Thin plate | 6.0 | 6.33 |
What might be the reason for the varied observations of the two students?
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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