Advertisements
Advertisements
प्रश्न
What is a short circuit?
Advertisements
उत्तर
Due to a fault in the equipment or if the plastic coating on the ‘live’ and the ‘neutral’ wires gives away the two wires come in contact with each other and a large current flows through it producing heat. This is known as short circuit.
APPEARS IN
संबंधित प्रश्न
An electric iron of resistance 20 Ω takes a current of 5 A. Calculate the heat developed in 30 s.
An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.
When current is switched ‘on’ in a room heater, it ______.
What is nichrome? State its one use.
An electric iron of resistance 20 ohms draws a current of 5 amperes. Calculate the heat produced in 30 seconds.
The current passing through a room heater has been halved. What will happen to the heat produced by it?
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
Which of the following characteristic is not suitable for a fuse wire?
(a) thin and short
(b) thick and short
(c) low melting point
(d) higher resistance than rest of wiring
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 reasons.
In the electric equipment producing heat e.g. iron, electric heater, boiler, toaster etc, an alloy such as Nichrome is used, not pure metals.
Give Scientific reason.
In practice, the unit kWh is used for the measurement of electrical energy, rather than joule.
Solve the following example.
Two tungsten bulbs of wattage 100 W and 60 W power work on 220 V potential difference. If they are connected in parallel, how much current will flow in the main conductor?
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.
A coil of an alloy _______ is used in electric heater cooker as a resistor.
Find the odd one out and give its explanation.
What is the heating effect of electric current?
Which metal is used to make the filament of an electric bulb?
When does overloading occur?
Explain the application of heating effect of electric current in an electric bulb with a diagram.
Explain the heating effect of electric current.
Heating effect of current is called ______
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 component used as a safety device is electric circuit is ______.
Can we use the same fuse in a geyser and a television set? Explain.
Name two electric devices for each where
- heating effect of current is used and
- magnetic effect of current is used.
An MCB can be used instead of a fuse in an electrical circuit.
What is an electric fuse made up of?
Explain the working of an electric fuse.
A student boils water in an electric kettle for 20 minutes. Using the same mains supply he wants to reduce the boiling time of water. To do so should he increase or decrease the length of the heating element? Justify your answer.
A trip switch is a ______ safety device.
A fuse is used in an electric circuit to stop high currents flowing through the circuit.
In which of the following applications of Iron, rusting will occur most? Support your answer with valid reason.
| A | B | C | D |
![]() |
![]() |
![]() |
![]() |
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.
What is the heating effect of electric current?
State the law that explains the heating effect of current with respect to the measurable properties in an electrical circuit.
The graph of voltage vs current for four different materials is shown below.

Which of these four materials would be used for making filament of bulb?
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.




