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प्रश्न
Why are the coils of electric irons and electric toasters made of an alloy rather than a pure metal?
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उत्तर
The coils of the heating elements of electric irons and electric toasters are made of alloys like nichrome rather than a pure metal because alloys have a high resistance and a high melting point.
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संबंधित प्रश्न
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.
(a) How much charge flows around the circuit each second?
Give two reasons why nichrome alloy is used for making the heating elements of electrical appliances.
Why does the connecting cord of an electric heater not glow hot while the heating element does?
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?
Give Scientific reason.
In practice, the unit kWh is used for the measurement of electrical energy, rather than joule.
Name some devices that run using heat effect of electric current
Which of the following is correct?
An electric iron draws a current of 4 A when connected to 220 V mains. Its resistance must be:
An electric bulb is connected to a 220 V generator. The current is 0.50 A. What is the power of the bulb?
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
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.
______ wire is used in the filament of the bulbs.
Fuse is a strip of alloy wire which is made up of lead and tin with a very low ______.
An electrochemical cell converts ______ energy into ______ energy.
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.
State the law that explains the heating effect of current with respect to the measurable properties in an electrical circuit.
