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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
State four most common electrical appliances based on heating effect of electric current. Why do we use finely heated platinum wire in surgery?
Why does the cord of an electric heater not glow while the heating element does?
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.
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.
(a) How much charge flows around the circuit each second?
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?
Give two reasons why nichrome alloy is used for making the heating elements of electrical appliances.
An electric kettle rated at 220 V, 2.2 kW, works for 3 hours. Find the energy consumed and the current drawn.
Explain why, tungsten is used for making the filaments of electric bulbs.
The current passing through a room heater has been halved. What will happen to the heat produced by 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
How does the wire in the filament of a light bulb behave differently to the other wires in the circuit when the current flows?
What property of the filament wire accounts for this difference?
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:
For electric power transmission, copper or aluminium wire is used.
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.
Answer the following question:
what is the heating effect of the electric current? state any four applications of it?
Answer the following question.
Write the mathematical expression for Joule's law of heating.
In an electric bulb, coil of _______ metal is used.
What is a short circuit?
What is used to turn off the sudden increase in current in the electrical circuit of the house nowadays?
Live wire and neutral wires have a 220 V potential difference.
Explain the application of heating effect of electric current in an electric bulb with a diagram.
Define fuse.
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?
A fuse wire repeatedly gets burnt when used with a good heater. It is advised to use a fuse wire of:
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.
An electric cell produces electricity from the ______ ______ in it.
What are the uses of electromagnets?
What is an electric fuse made up of?
What are the factors affecting heating effect of electric current?
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 |
Explain why fuse wire is always connected in a series arrangement.
Define the following:
Electrolyte
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 consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?
An electric iron of resistance 20 Ω draws a current of 5 A. The heat developed in the iron in 30 seconds is ______.
