A convex lens of focal length `25 cm` is placed co-axially in contact with a concave lens of focal length `20 cm`. Determine the power of the combination. Will the system be converging or diverging in nature ?

Explanation

To solve the problem, we will follow these steps:

### Step 1: Identify the Focal Lengths
We have a convex lens with a focal length \( f_1 = 25 \, \text{cm} \) and a concave lens with a focal length \( f_2 = -20 \, \text{cm} \) (the negative sign indicates that it is a concave lens).

### Step 2: Calculate the Power of Each Lens
The power \( P \) of a lens is given by the formula:
\[
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