Question

The strength of an electromagnet cannot be increased by

• A. increasing current in the coil.
• B. increasing the number of turns in the coil.
• C. reversing polarity of the battery.
• D. using core of larger cross-section.

Answer 1

The correct option is C reversing polarity of the battery.

The strength of an electromagnet depends on following factors.
1. If current in the coil of electromagnet is increased, its strength increases.
2. If we increase number of turns in the coil, its strength will increase.
3. By using core of larger cross- section also, the strength of an electromagnet can be enhanced.

But, if we are reversing the polarity of battery, it will simply reverse the poles of the electromagnet. There will not be any impact of it on the strength of the electromagnet.