Advertisements
Advertisements
प्रश्न
What is overloading?
Advertisements
उत्तर
When consumption of electrical power is huge, excessive current is drawn from the transformer supplying the electricity, and if the capacity of the transformer is insufficient, its fuse wire melts and the supply gets shutdown. Such events as called as overloading.
संबंधित प्रश्न
The safety device based on the heating effect of electric current is called a ______.
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?
What is nichrome? State its one use.
Give two reasons why nichrome alloy is used for making the heating elements of electrical appliances.
What is meant by the heating effect of current? Give two applications of the heating effect of current.
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 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.
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?
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.
Write the mathematical expression for Joule's law of heating.
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.
Explain the importance/uses of fuse wire.
When does overloading occur?
True or False – If False give the correct answer
The fuse wire does not melts whenever there is overload in the wiring.
Name any two appliances which work under the principle of heating effect of current.
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?
Why is parallel arrangement used in domestic wiring?
B1, B2 and B3 are three identical bulbs connected as shown in Figure. When all the three bulbs glow, a current of 3A is recorded by the ammeter A.
- What happens to the glow of the other two bulbs when the bulb B1 gets fused?
- What happens to the reading of A1, A2, A3 and A when the bulb B2 gets fused?
- How much power is dissipated in the circuit when all the three bulbs glow together?
Three incandescent bulbs of 100 W each are connected in series in an electric circuit. In another circuit another set of three bulbs of the same wattage are connected in parallel to the same source.
- Will the bulb in the two circuits glow with the same brightness? Justify your answer.
- Now let one bulb in both the circuits get fused. Will the rest of the bulbs continue to glow in each circuit? Give reason.
An electric component used as a safety device is electric circuit is ______.
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.
______ wire is used in the filament of the bulbs.
Copper wire offers very little ______ and does not get heated up quickly.
An electric fuse is a wire made up of a material having ______ melting point.
The electric fuse works on the Joule heating principle.
Explain why fuse wire is always connected in a series arrangement.
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.
1 kWh is equal to ______.
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 ______.
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.
