To make a simple electromagnet in a school laboratory, which of the following items are required?

Introduction / Context:

Electromagnets are magnets produced by the flow of electric current through a coil. They are widely used in electric bells, relays, cranes, and many other devices. In school experiments, students build a simple electromagnet to understand how electricity and magnetism are related. This question asks which components are needed to construct such an electromagnet.

Given Data / Assumptions:

• We want a simple electromagnet that works on direct current.
• A coil of wire carrying current must be wound around a magnetic core.
• A suitable power source and core material are available in the options.

Concept / Approach:

When electric current passes through a conductor, it produces a magnetic field around it. Winding the conductor into a coil concentrates the field. Placing a soft iron core inside the coil further strengthens the field because the core becomes magnetised. To maintain current in the coil, a direct current source, such as dry cell batteries, is required. Therefore, we need three things together: a power source, an insulated copper wire to form the coil, and a soft iron core such as a nail.

Step-by-Step Solution:

Verification / Alternative check:

A typical classroom experiment uses exactly these components. Students wrap insulated copper wire around an iron nail, connect the ends of the wire to a battery, and then observe that the nail can attract small paper clips, showing that an electromagnet has been created.

Why Other Options Are Wrong:

Option A: A power source alone cannot form a magnet without a coil and core.

Option B: A coil of wire alone, without current, does not create a meaningful magnetic field.

Option C: A soft iron nail alone has only weak magnetism and does not become a strong magnet without a surrounding current carrying coil.

Common Pitfalls:

Some learners think that any piece of iron connected to a battery becomes an electromagnet, but without many turns of wire, the field is very weak. Others forget the need for insulation on the wire so that turns do not short circuit. Remember that a complete electromagnet setup requires all the components listed together.

Final Answer:

To make a simple electromagnet you need all of the above components together.