Electromagnets

Q. What is electromagnet

Q.

The principle on which an electric bell works on is ____________

1. Heating and chemical effect

2. Heating effect

3. Chemical effect

4. Magnetic effect

Q. Why is insulated wire used in an electromagnet around a soft iron core?

1. As insulated wire does not maintain conductivity.
2. As insulated wires are more prone to shorts.
3. To prevent the contact of the wires with each other.
4. All of the above.

Q.

Which among the following devices work(s) on the basis of the magnetic effect of electric current?

1. Electric bell

2. Electric heater

3. Crane

4. Electric fuse

Q.

Which of the following material can be used as a core for making an electromagnet?

1. Silver

2. Steel

3. Rubber

4. Soft iron

Q. Electric Bell works on the principle of:

1. Chemical Effect of Electric Current
2. Heating Effect of Electric Current
3. Magnetic Effect of Electric Current
4. Resisting Effect of Electric Current

Q. Which of the following statement are true for an electromagnet?

1. Electromagnets are created by passing electricity through a conductor.
2. Electromagnets are created by heating a conductor.
3. Electromagnets are permanent magnets.
4. Electromagnets are temporary magnets.

Q. An electric bell works on the ______ of electric current.

1. Heating effect
2. Magnetic effect
3. Chemical effect
4. (a) and (c) above.

Q.

Statements given below are incorrect. Write the correct statements.

When a soft iron rod is placed in an insulated coil carrying current, it changes into permanent magnet.

Q. Compare the magnetic properties of soft iron and steel.

Q. In which of the following cases, the strength of an electromagnet can be increased?

1. Increasing the current.
2. Increasing the number of turns.
3. Using soft iron core of larger cross section.
4. Changing the direction of current in electromagnet.

Q.

Electric bell is an example of a/an _____________

1. Bar magnet

2. Electromagnet

3. Cylindrical magnet

4. Horse shoe magnet

Q. Which of the following uses electromagnets to operate?

1. Coal train
2. Maglev train
3. Electric train
4. Cargo train

Q.

List two ways of increasing the strength of an electromagnet if the material of the electromagnet is fixed.

Q. Explain susceptibility and retentivity.
A student was given a random strip of a metal that is to be made into a magnet.
Explain the properties of the metal strip in terms of magnetic susceptibility and retentivity, if it to be made into a:

1. Temporary magnet
2. Permanent magnet

Q.

Electromagnets work on the principle of

1. Heating effect of electric current

2. Electro-chemical effect of electric current

3. Magnetic effect of electric current

4. Chemical effect of electric current

Q.

Whenever a magnet is not in use, it should be stored along with the other magnets.

1. True
2. False

Q. A crane uses an object ‘X’ to separate magnetic materials from junk. The object ‘X’ is most probably:

1. Iron rod
2. Electromagnet
3. Permanent magnet
4. Lodestone

Q.

Why do we use insulated copper wire while making electromagnets ?

1. To avoid short circuit

2. To make it look good

3. All of the above

4. To protect it from sunlight

Q. You are provided with two identical metal bars. One out of the two is a magnet. Suggest two ways to identify the magnet.

Q. Write a short note on electric bell. Explain it's construction and working with the help of the diagram. [5 Marks]

Q.

The materials suitable for making electromagnets should have

Q. Arrange the strength of below electromagnets in ascending order based on number of coils and current flowing.

1. 10 coils, 30 A
2. 10 coils, 70 A
3. 10 coils, 20 A
4. 10 coils, 10 A

Q.

Which of the following devices use electromagnets?

1. Electric heater

2. Washing machine

3. Bulb

4. Electric bell

Q.

Is it possible to discharge the capacitor?

Q.

Statements given below are incorrect. Write the correct statements.

When current flows around a soft iron, it changes into permanent magnet.

Q.

The following arrangement will behave as an electromagnet. Say true or false.

1. False

2. True

Q.

Which of the following is not true about electromagnets?

1. The strength cannot be changed

2. The polarity can be changed

3. Uses insulated copper wire for coating

4. The magnetic property is due to current

Q.

The below arrangement in its current state can attract iron filings if ___________

i) the switch is closed.

ii) the terminals are reversed and the switch is closed.

1. Only i) is correct

2. Both i) and ii) are correct

3. Only ii) is correct

4. None of these

Q. Question 12

Deflection occurs in the magnetic coil due to?