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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.

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प्रश्न

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.

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उत्तर

In the electric equipment producing heat, such as iron, electric heater, boiler, toaster etc., an alloy such as Nichrome is used, not pure metals because of the following reasons:

  1. Resistivity of Nichrome is more compared to pure metal.
  2. Melting point of Nichrome is high as compared to pure metal.
  3. Nichrome does not get oxidised when heated in air whereas metal does.
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अध्याय 4: Effects of electric current - Exercise [पृष्ठ ६१]

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बालभारती Science and Technology Part 1 [English] Standard 10 Maharashtra State Board
अध्याय 4 Effects of electric current
Exercise | Q 7. b. | पृष्ठ ६१

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.


Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?


Name any two effects of electric current.


An electric heater is connected to the 230 V mains supply. A current of 8 A flows through the heater.

  1. How much charge flows around the circuit each second?
  2. How much energy is transferred to the heater each second?

An electric room heater draws a current of 2.4 A from the 120 V supply line. What current will this room heater draw when connected to 240 V supply line?


An electric kettle rated at 220 V, 2.2 kW, works for 3 hours. Find the energy consumed and the current drawn.


A heating coil has a resistance of 200 Ω. At what rate will heat be produced in it when a current of 2.5 A flows through it?


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? 


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Rewrite the following statement by selecting the correct option:

1 A = ____________ mA.


The ‘live’ and the ‘neutral’ wires have potential difference of _______.


A coil of an alloy _______ is used in electric heater cooker as a resistor.


Which of the following substance contracts on heating?


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?


An electric iron draws a current of 4 A when connected to 220 V mains. Its resistance must be:


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Reason: The resistance of a conductor depends on length, thickness, nature of material and temperature of the conductor.


Why is parallel arrangement used in domestic wiring?


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.


Name two electric devices for each where

  1. heating effect of current is used and
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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.


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What are the factors affecting heating effect of electric current?


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Name the effect of the current responsible for the glow of the bulb in an electrical circuit.


The following is not a safety device.


An electric fuse is a wire made up of a material having ______ melting point.


A trip switch is a ______ safety device.


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?


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.


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