मराठी

Why Are the Coils of Electric Irons and Electric Toasters Made of an Alloy Rather than a Pure Metal? - Science

Advertisements
Advertisements

प्रश्न

Why are the coils of electric irons and electric toasters made of an alloy rather than a pure metal?

Advertisements

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.

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 1: Electricity - Exercise 3

APPEARS IN

व्हिडिओ ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्‍न

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?


How does the resistance of a wire vary with its: 

 diameter? 

 


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


Explain why, the current that makes the heater element very hot, only slightly warms the connecting wires leading to the heater.


Give a scientific reason.

Tungsten metal is used to make a solenoid type coil in an electric bulb.


Give a scientific reason:

For electric power transmission, copper or aluminium wire is used.


Write the mathematical expression for Joule’s law of heating.


In an electric bulb, coil of _______ metal is used.


The electricity bill specifies the usage in _______.


When does overloading occur?


How can overloading be avoided?


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


The heating element of an electric iron is made up of:


When a switch is in OFF position,

  1. circuit starting from the positive terminal of the cell stops at the switch.
  2. circuit is open.
  3. no current flows through it.
  4. current flows after some time. 

Choose the combination of correct answer from the following.


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.


What are the factors affecting heating effect of electric current?


Explain the working of an electric fuse.


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.


The electric fuse works on the Joule heating principle.


When a current I flows through a wire of resistance R for time t then the electrical energy produced is given by ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×