Which of the following actions will decrease the strength of the magnetic field of an electromagnet?

Options

A. using few loops of wire per metre in the coil
B. decreasing the current in the wire
C. removing the iron core
D. All of the above

Explanation

To determine which actions will decrease the strength of the magnetic field of an electromagnet, we can analyze the effects of each action on the electromagnet's design and functionality.

### Step-by-Step Solution:

1. **Understanding Electromagnets**: An electromagnet consists of a coil of wire (usually copper) wound around a core material (often soft iron). When an electric current flows through the wire, it generates a magnetic field.

2. **Factors Affecting Magnetic Field Strength**:
- **Current Strength**: The strength of the magnetic field is directly proportional to the amount of electric current flowing through the wire. If the current is decreased, the magnetic field strength will also decrease.
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