x-y plane separates two media, `zge0` contains a medium of refractive index 1 and `zle0` contains a medium of refractive index 2. A ray of light is incident from first medium along a vector`hati+hatj-hatk`. Find the unit vector along the refracted ray.

Explanation

To solve the problem, we will use Snell's law, which relates the angles of incidence and refraction to the refractive indices of the two media.

### Step-by-step Solution:

1. **Identify the Given Information:**
- The refractive index of the first medium (z ≥ 0) is \( \mu_1 = 1 \).
- The refractive index of the second medium (z ≤ 0) is \( \mu_2 = 2 \).
- The incident ray is given by the vector \( \hat{i} + \hat{j} - \hat{k} \).
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