Question

For a current in a long straight solenoid N- and S-poles are created at the two ends. Among the following statements, the incorrect statement is (a) The field lines inside the solenoid are in the form of straight lines which indicates that the magnetic field is the same at all points inside the solenoid (b) The strong magnetic field produced inside the solenoid can be used to magnetise a piece of magnetic material like soft iron, when placed inside the coil (c) The pattern of the magnetic field associated with the solenoid is different from the pattern of the magnetic field around a bar magnet (d) The N- and S-poles exchange position when the direction of current through the solenoid is reversed

• A. The field lines inside the solenoid are in the form of straight lines which indicates that the magnetic field is the same at all points inside the solenoid
• B. The strong magnetic field produced inside the solenoid can be used to magnetise a piece of magnetic material like soft iron, when placed inside the coil
• C. The pattern of the magnetic field associated with the solenoid is different from the pattern of the magnetic field around a bar magnet
• D. The N- and S-poles exchange position when the direction of current through the solenoid is reversed

Answer 1

The correct option is C

The pattern of the magnetic field associated with the solenoid is different from the pattern of the magnetic field around a bar magnet

Explanation for the correct option:

Option C:

1. Solenoid behaves like a bar magnet in multiple ways.
2. The pattern of the magnetic field of the solenoid is the same as the pattern of the magnetic field around a bar magnet.
3. Hence, this is the correct option.

Explanation for the incorrect options:

Option A:

1. As a solenoid acts as a bar magnet, the field lines inside also act the same as that of a bar magnet.
2. They are parallel, straight lines which indicates that the magnetic field is the same at all points inside the solenoid.
3. Hence, this is not the correct option.

Option B:

1. A steel bar placed inside a solenoid will experience very strong magnetic field and can be easily magnetized.
2. Hence, this is not the correct option.

Option D:

1. As solenoid acts as a bar magnet, it will behave the same when the direction of the electricity is changed by changing the poles.
2. Hence, this is not the correct option.

Hence, option C is the correct option.