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प्रश्न
The electricity bill specifies the usage in _______.
विकल्प
kilowatt
joule
volt
unit
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उत्तर
The electricity bill specifies the usage in unit.
APPEARS IN
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?
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.
An electric kettle rated at 220 V, 2.2 kW, works for 3 hours. Find the energy consumed and the current drawn.
Why does the connecting cord of an electric heater not glow hot while the heating element does?
An electric iron of resistance 20 ohms draws a current of 5 amperes. Calculate the heat produced in 30 seconds.
Explain why, the current that makes the heater element very hot, only slightly warms the connecting wires leading to the heater.
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
The electrical resistivities of four materials P, Q, R and S are given below:
| P | `6.84xx10^8`Ωm |
| Q | `1.70xx10^8`Ωm |
| R | ` 1.0xx10^15`Ωm |
| s | `11.0xx10^-7`Ωm |
Which material will you use for making: (a) heating element of electric iron (b) connecting wires of electric iron (c) covering of connecting wires? Give reason for your choice in each case.
How does the wire in the filament of a light bulb behave differently to the other wires in the circuit when the current flows?
What property of the filament wire accounts for this difference?
Which electric heating device in your home do you think have resistors which control the flow of electricity?
Give a scientific reason:
For electric power transmission, copper or aluminium wire is used.
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).
Name any six domestic appliances based on the heating effect of electric current.
Rewrite the following statement by selecting the correct option:
1 A = ____________ mA.
What is the heating effect of electric current?
What is overloading?
Live wire and neutral wires have a 220 V potential difference.
Heating effect of current is called ______
Name any two appliances which work under the principle of heating effect of current.
Which of the following gases are filled in electric bulbs?
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.
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 ______.
Copper wire offers very little ______ and does not get heated up quickly.
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.
What is a trip switch?
An electrochemical cell converts ______ energy into ______ energy.
A trip switch is a ______ safety device.
The electric fuse works on the Joule heating principle.
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?
1 kWh is equal to ______.
In the electric equipment producing heat like iron, electric heater, boiler, toaster etc., an alloy such as nichrome is used, not pure metals.
In which of the following applications of Iron, rusting will occur most? Support your answer with valid reason.
| A | B | C | D |
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An electric kettle of 2 kW is used for 2h. Calculate the energy consumed in
- kilowatt hour and
- joules.
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 ______.
