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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
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?
Name any two effects of electric current.
When current is switched ‘on’ in a room heater, it ______.
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?
What is meant by the heating effect of current? Give two applications of the heating effect of current.
The heat produced by passing an electric current through a fixed resistor is proportional to the square of:
(a) magnitude of resistance of the resistor
(b) temperature of the resistor
(c) magnitude of current
(d) time for which current is passed
The elements of electrical heating devices are usually made of:
(a) tungsten
(b) bronze
(c) nichrome
(d) argon
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.
Tungsten metal is used to make a solenoid type coil in an electric bulb.
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.
Why does tungsten metal used to make solenoid type coil in an electric bulb?
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.
Name any six domestic appliances based on the heating effect of electric current.
Rewrite the following statement by selecting the correct option:
1 A = ____________ mA.
Answer the following question:
what is the heating effect of the electric current? state any four applications of it?
Which metal is used to make the filament of an electric bulb?
What is a short circuit?
What is used to turn off the sudden increase in current in the electrical circuit of the house nowadays?
Name any two appliances which works on the phenomenon of heating effect of electric current.
When does overloading occur?
An electric iron draws a current of 4 A when connected to 220 V mains. Its resistance must be:
Which of the following gases are filled in electric bulbs?
When a switch is in OFF position,
- circuit starting from the positive terminal of the cell stops at the switch.
- circuit is open.
- no current flows through it.
- current flows after some time.
Choose the combination of correct answer from the following.
An electric cell produces electricity from the ______ ______ in it.
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.
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.
Explain the working of an electric fuse.
Match the following
| 1. | Bulb | a. | Conductor |
| 2. | Electroplating | b. |
Insulator |
| 3. | Pure water | c. | Heating effect of current |
| 4. | Salt solution | d. | Chemical effect of current |
A student boils water in an electric kettle for 20 minutes. Using the same mains supply he wants to reduce the boiling time of water. To do so should he increase or decrease the length of the heating element? Justify your answer.
The following is not a safety device.
The electric fuse works on the Joule heating principle.
Define the following:
Electrolyte
If 220 V potential difference is applied across an electric bulb, a current of 0.45 A flows in the bulb. What must be the power of the bulb?
Find the odd one out.
In which of the following applications of Iron, rusting will occur most? Support your answer with valid reason.
| A | B | C | D |
 |
 |
 |
 |
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.
An electric iron of resistance 20 Ω draws a current of 5 A. The heat developed in the iron in 30 seconds is ______.
