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प्रश्न
A coil of an alloy _______ is used in electric heater cooker as a resistor.
विकल्प
Stainless steel
Nichrome
Copper
Bronze
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उत्तर
A coil of an alloy nichrome is used in electric heater cooker as a resistor.
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संबंधित प्रश्न
Name any two effects of electric current.
The safety device based on the heating effect of electric current is called a ______.
Write Joule's law of heating.
An electric room heater draws a current of 2.4 A from the 120 V supply line. What current will this room heater draw when connected to 240 V supply line?
Why is a series arrangement not used for connecting domestic electrical appliances in a circuit?
Explain why, tungsten is used for making the filaments of electric bulbs.
Derive the expression for the heat produced due to a current 'I' flowing for a time interval 't' through a resistor 'R' having a potential difference 'V' across its ends. With which name is this relation known?
The current passing through an electric kettle has been doubled. The heat produced will become:
(a) half
(b) double
(c) four time
(d) one-fourth
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
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.
Which electric heating device in your home do you think have resistors which control the flow of electricity?
Three heaters each rated 250 W, 100 V are connected in parallel to a 100 V supply. Calculate:
- the total current taken from the supply
- the resistance of each heater and
- the energy supplied in kWh to the three heaters in 5 hours.
Give a scientific reason.
Tungsten metal is used to make a solenoid type coil in an electric bulb.
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.
Answer the following question:
what is the heating effect of the electric current? state any four applications of it?
Compute the heat generated while transferring 96000 coulombs of charge in two hours through a potential difference of 40 V.
Which metal is used to make the filament of an electric bulb?
What is overloading?
What is used to turn off the sudden increase in current in the electrical circuit of the house nowadays?
Write two devices based on the heating effect of electric current.
When does overloading occur?
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?
An electric iron draws a current of 4 A when connected to 220 V mains. Its resistance must be:
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:
What is Joule’s heating effect? How can it be demonstrated experimentally? List its four applications in daily life.
An electric component used as a safety device is electric circuit is ______.
What are the factors affecting heating effect of electric current?
______ wire is used in the filament of the bulbs.
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 |
The following is not a safety device.
An electric fuse is a wire made up of a material having ______ melting point.
In a set up the students coated iron nails with zinc metal and noted that, iron nails coated with zinc prevents rusting. They also observed that zinc initially acts as a physical barrier, but an extra advantage of using zinc is that it continues to prevent rusting even if the layer of zinc is damaged. Name this process of rust prevention and give any two other methods to prevent rusting.
An electric kettle of 2 kW is used for 2h. Calculate the energy consumed in
- kilowatt hour and
- joules.
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?
When a current I flows through a wire of resistance R for time t then the electrical energy produced is given by ______.
