A convex glass lens `( mu = 1.5 )` produces a real image of an object. The size of the image equals the size of the object. When the air surrounding the lens is replaced by a liquid, the size of the image is found to be twice that of the object. Find the refractive index of the liquid.

Explanation

To solve the problem step by step, we will use the lens formula and the concept of magnification.

### Step 1: Understand the Magnification in the Air
The magnification \( M \) of a lens is given by the formula:
\[ M = \frac{H_I}{H_O} = \frac{V}{U} \]
where \( H_I \) is the height of the image, \( H_O \) is the height of the object, \( V \) is the image distance, and \( U \) is the object distance.
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