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प्रश्न
What is used to turn off the sudden increase in current in the electrical circuit of the house nowadays?
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उत्तर
Nowadays, Miniature Circuit Breakers (MCB) is used to turn off the sudden increase in current in the electrical circuit of the house.
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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?
How does the resistance of a wire vary with its area of cross-section?
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?
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 an electric kettle has been doubled. The heat produced will become:
(a) half
(b) double
(c) four time
(d) one-fourth
Which electric heating device in your home do you think have resistors which control the flow of electricity?
Identify the figure and give its use.
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?
Why does tungsten metal used to make solenoid type coil in an electric bulb?
Solve the following question.
Compute the heat generated while transferring 96000 coulombs of charge in two hours through a potential difference of 40 V.
These days when current in the circuit suddenly increases _______ switches are used.
Which of the following substance contracts on heating?
Find the odd one out and give its explanation.
Write two devices based on the heating effect of electric current.
Live wire and neutral wires have a 220 V potential difference.
Explain the importance/uses of fuse wire.
When does overloading occur?
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:
The heating element of an electric iron is made up of:
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?
What is Joule’s heating effect? How can it be demonstrated experimentally? List its four applications in daily life.
An electric cell produces electricity from the ______ ______ in it.
Unscramble the following words:
SFEU
An MCB can be used instead of a fuse in an electrical circuit.
______ wire is used in the filament of the bulbs.
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 |
What is a trip switch?
Explain why fuse wire is always connected in a series arrangement.
Tara, after completing her exams, went to her grandmother's house along with her younger brother Rahul. One day, Rahul came home after playing and switched on the fan and air conditioner. At the same time, his grandmother was preparing a milkshake for him using a mixer. Suddenly, they heard a big sound and the electricity of the house got shut down. Tara is called an electrician. He said the main reason for supply to shut down was overloading.
- What is overloading?
- Is overloading and short the same? When does short-circuiting take place?
- How can the effects of overloading be avoided?
Two students decided to investigate the effect of water and air on iron object under identical experimental conditions. They measured the mass of each object before placing it partially immersed in 10 ml of water. After a few days, the object were removed, dried and their masses were measured. The table shows their results.
| Student | Object | Mass of Object before Rusting in g |
Mass of the coated object in g |
| A | Nail | 3.0 | 3.15 |
| B | Thin plate | 6.0 | 6.33 |
What might be the reason for the varied observations of the two students?
When a current I flows through a wire of resistance R for time t then the electrical energy produced is given by ______.
An electric iron of resistance 20 Ω draws a current of 5 A. The heat developed in the iron in 30 seconds is ______.
