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प्रश्न
The current passing through a room heater has been halved. What will happen to the heat produced by it?
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उत्तर
The heat produced by the room heater will become one-fourth the previous quantity when the current passing through it is halved because the heat produced is directly proportional to the square of the current.
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संबंधित प्रश्न
Why is the tungsten used almost exclusively for filament of electric lamps?
Name any two effects of electric current.
Explain why, the current that makes the heater element very hot, only slightly warms the connecting wires leading to the heater.
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
The heat produced in a wire of resistance 'x' when a current 'y' flows through it in time 'z' is given by:
(a) x2 × y × z
(b) x × z × y2
(c) y × z2 × x
(d) y × z × x
Two exactly similar heating resistances are connected (i) in series, and (ii) in parallel, in two different circuits, one by one. If the same current is passed through both the combinations, is more heat obtained per minute when they are connected in series or when they are connected in parallel? Give reason for your answer.
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.
Name any six domestic appliances based on the heating effect of electric current.
What does overloading cause?
True or False – If False give the correct answer
The fuse wire does not melts whenever there is overload in the wiring.
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 draws a current of 4 A when connected to 220 V mains. Its resistance must be:
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.
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.
What are the uses of electromagnets?
An electrochemical cell converts ______ energy into ______ energy.
An electric kettle of 2 kW is used for 2h. Calculate the energy consumed in
- kilowatt hour and
- joules.
