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प्रश्न
In an electric bulb, coil of _______ metal is used.
पर्याय
copper
tungsten
aluminium
iron
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उत्तर
In an electric bulb, coil of tungsten metal is used.
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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 is the tungsten used almost exclusively for filament of electric lamps?
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 are the coils of electric irons and electric toasters made of an alloy rather than a pure metal?
A resistance of 25 Ω is connected to a 12 V battery. Calculate the heat energy in joules generated per minute.
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
Give Scientific reason.
In practice, the unit kWh is used for the measurement of electrical energy, rather than joule.
Identify the figure and give its use.
Heat energy is being produced in a resistance in a circuit at the rate of 100 W. The current of 3 A is flowing in the circuit. What must be the value of the resistance?
An electric iron of 1100 W is operated for 2 hrs daily. What will be the electrical consumption expenses for that in the month of April? (The electric company charges Rs 5 per unit of energy).
Compute the heat generated while transferring 96000 coulombs of charge in two hours through a potential difference of 40 V.
The electricity bill specifies the usage in _______.
What is the heating effect of electric current?
What is overloading?
How can overloading be avoided?
True or False – If False give the correct answer
The fuse wire does not melts whenever there is overload in the wiring.
Define fuse.
Heating effect of current is called ______
Which of the following is correct?
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.
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.
Unscramble the following words:
SFEU
Name two electric devices for each where
- heating effect of current is used and
- magnetic effect of current is used.
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.
What are the uses of electromagnets?
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 |
An electrochemical cell converts ______ energy into ______ energy.
A trip switch is a ______ safety device.
A fuse is used in an electric circuit to stop high currents flowing through the circuit.
Find the odd one out.
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.
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?
An electric iron is rated 220 V, 2 kW. If the iron is used for 3h daily find the cost of running it for one week if it costs ₹ 4.25 per kWh.
