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प्रश्न
Name any six domestic appliances based on the heating effect of electric current.
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उत्तर
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संबंधित प्रश्न
Why does the cord of an electric heater not glow while the heating element does?
Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?
How does the resistance of a wire vary with its area of cross-section?
Give two reasons why nichrome alloy is used for making the heating elements of electrical appliances.
Derive the expression for the heat produced due to a current 'I' flowing for a time interval 't' through a resistor 'R' having a potential difference 'V' across its ends. With which name is this relation known?
How much heat will an instrument of 12 W produce in one minute if it is connected to the heat produced by it?
The heat produced by passing an electric current through a fixed resistor is proportional to the square of:
(a) magnitude of resistance of the resistor
(b) temperature of the resistor
(c) magnitude of current
(d) time for which current is passed
The elements of electrical heating devices are usually made of:
(a) tungsten
(b) bronze
(c) nichrome
(d) argon
The heat produced in a wire of resistance 'x' when a current 'y' flows through it in time 'z' is given by:
(a) x2 × y × z
(b) x × z × y2
(c) y × z2 × x
(d) y × z × x
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 a scientific reason.
Tungsten metal is used to make a solenoid type coil in an electric bulb.
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.
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).
Rewrite the following statement by selecting the correct option:
1 A = ____________ mA.
Compute the heat generated while transferring 96000 coulombs of charge in two hours through a potential difference of 40 V.
In an electric bulb, coil of _______ metal is used.
Live wire and neutral wires have a 220 V potential difference.
What does overloading cause?
A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross-section of the filament in 16 seconds would be roughly:
An electric bulb is connected to a 220 V generator. The current is 0.50 A. What is the power of the bulb?
An electric component used as a safety device is electric circuit is ______.
An electric cell produces electricity from the ______ ______ in it.
Can we use the same fuse in a geyser and a television set? Explain.
Paheli took a wire of length 10 cm. Boojho took a wire of 5 cm of the same material and thickness. Both of them connected the wires as shown in the circuit given in the following figure. The current flowing in both the circuits is the same.
- Will the heat produced in both cases be equal? Explain.
- Will the heat produced be the same if the wires taken by them are of equal lengths but of different thickness? Explain.
What are the uses of electromagnets?
Name the effect of the current responsible for the glow of the bulb in an electrical circuit.
An electric fuse is a wire made up of a material having ______ melting point.
A trip switch is a ______ safety device.
A fuse is used in an electric circuit to stop high currents flowing through the circuit.
Explain why fuse wire is always connected in a series arrangement.
Define the following:
Electrolyte
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?
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.
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.
When a current I flows through a wire of resistance R for time t then the electrical energy produced is given by ______.
