Define magnetic flux density ( magnetic induction ) . The magnetic induction of a point is B. What is the magnetic flux through an area A ?

Explanation

### Step-by-Step Solution:

1. **Definition of Magnetic Flux Density**:
- Magnetic flux density, also known as magnetic induction (denoted as **B**), is defined as the number of magnetic field lines crossing a unit area that is kept perpendicular (normal) to the direction of the magnetic field.
- Mathematically, it can be expressed as:
\[ B = \frac{\Phi}{A} \]
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