Electric Bell

Q.

When we pass electricity through the coil, it produces magnetic field around the soft iron piece and this soft iron piece becomes electromagnet and its magnetic strength can be changed by changing the amount of current flowing the coil.
Electromagnets have various uses in the industry. It can be used to separate magnetic material from non-magnetic material as it will attract all the magnetic material, thus leaving behind all the non- magnetic material.
When we press the button for electric bell outside anyone's house, what happens? You hear a sound but that sound remains only till you press the button as soon as you remove your finger, the sound stops.

The mechanism which explains the bell out of the following is?

1. When you press the button, it opens the circuit and electricity flows through the iron piece and it becomes electromagnet and it attracts the striker towards it and in this process striker collides with bell, producing sound.

2. When you press the button, it closes the circuit and electricity flows through the iron piece and it becomes electromagnet and it attracts the striker towards it and in this process striker collides with bell, producing sound.

3. When you press the button, it simply strikes the bell and no electricity flows through it.

4. Bell does not use any electricity or any electromagnet.

Q.

Which appliance does not use electromagnet

Washing Machines, electric heater, electric bell, grinder

Q.

The standard frequency of electric power supply in India is ___ Hz.

Q.

Question 1

Observe the pictures A and B given in Fig. carefully.

Which of the following statement is correct for the above given pictures?

(a) In A, cars 1 and 2 will come closer and in B, cars 3 and 4 will come closer.

(b) In A, cars 1 and 2 will move away from each other and in B, cars 3 and 4 will move away.

(c) In A, cars 1 and 2 will move away and in B, 3 and 4 will come closer to each other

(d) In A, cars 1 and 2 will come closer to each other and in B, 3 and 4 will move away from each other.

Q. Draw a neat and labelled diagram of an electric bell and describe its working.

Q.

Use of armature in an electric bell

Also,

Describe how an electric bell works.

Q.

How electric bell is worked ?

Q. Explain the working of an electric bell.

Q.

Question 8

(i) Our body is a ___ of electricity.
(ii) An electric cell produces electricity from the ___ in it.
(iii) In an electric circuit a fuse is a ___, ___ to prevent possible fire.
(iv) A combination of two more cells is called a ___.

Q.

What are the various components of an electric bell? Explain the working of an electric bell. [5 MARKS]

Q. Write true or false for this statement:
An electric bell uses an electromagnet.

Q.

In an electric bell, when the electromagnet pulls the iron strip, it also breaks the circuit. The current through the coil stops flowing. In this case, will the coil remain an electromagnet? How does an electric bell ring then? [3 MARKS]

Q.

Question 9 (d)
Mark ‘T’ if the statement is true and ‘F’ if it is false:
An electric bell has an electromagnet.

Q. The switch of an electric bell is pressed. Now, arrange the following statements using the working of an electric bell.

(i) Electromagnet loses its magnetism and the striker goes back its original position.
(ii) The current flows through the circuit and electromagnet attracts the striker towards it.
(iii) The striker hits the gong and the circuit is broken.

1. (i), (ii), (iii)
2. (iii), (i), (ii)
3. (iii), (ii), (i)
4. (ii), (iii), (i)

Q. ntA coil in the shape of an equilateral triangle of side l is suspended between the pole pieces of a permanentntmagnet such that B is in plane of the coil. If due to a current i in the triangle a torque tau acts on it, the side lntof the triangle is :n

Q. Explain the construction and working of electric bell with figure.

Q. An electric bell works on the principle of effect of electric current.

1. heating
2. magnetic
3. chemical

Q. Which part of the electric bell vibrates to produce the sound that we listen?

1. 
2. 
3. 
4. 

Q. Name a safety device used in the electric circuit. What is the function of that safety device?

Q. The doorbell uses:

1. Electromagnet
2. Permanent magnet
3. Heating effect of current
4. Chemical effect of current

Q. How does the magnetic effect of electric current help in the working of an electric bell? Explain with the help of a diagram.

Q.

Name a device which works on the magnetic effect of current.

Q. Match the following.

1. Electromagnet
2. Lodestone
3. Double touch method
4. Magnetic induction

Q.

Magnets are used in _________ .

1. Mixer and grinder

2. Televisions

3. Doorbells

4. Both (B) and (C)

Q.

Which of the following is responsible for making and breaking the circuit in an electric bell?

1. Electromagnet

2. Contact Screw

3. Gong

4. Striker

Q.

In which of the following, the principle of chemical effects of electricity is used?

1. telephone

2. electroplating

3. electric bell

4. electric motor

Q. The switch of an electric bell is pressed. Now, arrange the following statements using the working of an electric bell.

(i) Electromagnet loses its magnetism and the striker goes back its original position.
(ii) The current flows through the circuit and electromagnet attracts the striker towards it.
(iii) The striker hits the gong and the circuit is broken.

1. (i), (ii), (iii)
2. (iii), (i), (ii)
3. (iii), (ii), (i)
4. (ii), (iii), (i)

Q.

In an electric bell, when the electromagnet pulls the iron strip, it also breaks the circuit. The current through the coil stops flowing. In this case, will the coil remain an electromagnet? How does an electric bell ring then?

Q.

Where is damping used?

Q. Where to use w=f.s and w=rf