Answer the following:
(a) Define wavefront. Use Huygens' principle to verify the laws of refraction.
(b) How is linearly polarised light obtained by the process of scattering of light? Find the Brewster angle for air-glass interface, when the refractive index of glass is `1.5` .

Explanation

### Step-by-Step Solution

#### (a) Define wavefront and verify the laws of refraction using Huygens' principle.

1. **Definition of Wavefront**:
- A wavefront is defined as a surface over which an oscillation or wave has a constant phase. In simpler terms, it is the surface formed by connecting all points that are vibrating in the same phase of a wave.

2. **Huygens' Principle**:
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