MCQs from NCERT Exemplar

Class 10
Chapter 13 Class 10 - Magnetic Effects of Electric Current

## (d) The N and S-poles exchange position when the direction of current through the solenoid is reversed.

Properties of magnetic field produced in a solenoid:

• A solenoid behaves like a bar magnet when current is passed through it.
• The field lines are parallel straight lines inside a solenoid which indicates that the magnetic field is uniform inside a solenoid.
• Magnetic field produced in a solenoid is very strong and hence they are used to make electromagnets.
• When direction of current is reversed i n a solenoid, the north and south poles are exchanged.

Checking the options:

• (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 - This is correct.
• (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  - This is correct.
• (c) The pattern of the magnetic field associated with  the solenoid is different from the pattern of the  magnetic field around a bar magnet  - This is incorrect, because a solenoid behaves like a bar magnet when electricity is passed through it.
• (d) The N and S-poles exchange position when the direction of current through the solenoid is reversed  - This is correct.

So, the correct answer is (c)

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