(b) Write the Lens Maker's formula and use it to obtain the range of `mu` (The refractive index of the material of the lens) for which the focal length of and equiconvex lens, kept in air, would have a greater magnitude than that of the radius of curvature of its two surfaces.

Explanation

### Step-by-Step Solution

1. **Write the Lens Maker's Formula**:
The Lens Maker's formula is given by:
\[ \frac{1}{f} = (\mu - 1) \left( \frac{1}{R_1} - \frac{1}{R_2} \right) \]
where \( f \) is the focal length of the lens, \( \mu \) is the refractive index of the lens material, and \( R_1 \) and \( R_2 \) are the radii of curvature of the two surfaces of the lens.
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