What is magnetic field? Give important properties of magnetic field lines.

Explanation

### Step-by-Step Text Solution:

**Step 1: Define Magnetic Field**
A magnetic field is defined as the space around a magnet where the force of attraction or repulsion can be detected. This force acts on other magnets or magnetic materials within this space. Specifically, attraction occurs when the poles of two magnets are unlike (North-South or South-North), while repulsion occurs when the poles are alike (North-North or South-South).

**Step 2: List Important Properties of Magnetic Field Lines**
1. **Emergence and Merging**: Magnetic field lines emerge from the North pole of a magnet and merge at the South pole. This means that the lines radiate outward from the North and curve around to enter the South pole.

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