A substance consisting of a coil of wire with an iron core and is only magnetized when electric current flow through it is called

Options

A. permanent magnet
B. electromagnet
C. battery
D. bar magnet

Explanation

To solve the question, we need to identify the substance described. The question states that it consists of a coil of wire with an iron core and is only magnetized when an electric current flows through it.

Here’s a step-by-step solution:

### Step 1: Understand the Components
- The question mentions a "coil of wire" and an "iron core." This indicates that we are dealing with a setup where electricity can influence magnetism.

**Hint for Step 1:** Think about how electricity and magnetism are related.

### Step 2: Identify the Function
- The key part of the question is that this substance is "only magnetized when electric current flows through it." This implies that it does not have permanent magnetism and relies on the flow of electricity to exhibit magnetic properties.

**Hint for Step 2:** Consider what types of magnets are temporary and depend on an external power source.

### Step 3: Recall the Term
- The combination of a coil of wire and an iron core that becomes magnetized with electric current is known as an "electromagnet." Electromagnets are temporary magnets that lose their magnetism when the current is turned off.

**Hint for Step 3:** Think about the term that describes a magnet created by electricity.

### Step 4: Conclusion
- Therefore, the answer to the question is that the substance described is called an **electromagnet**.

**Final Answer:** A substance consisting of a coil of wire with an iron core and is only magnetized when electric current flows through it is called an **electromagnet**.