A convex lens of power +5 D is placed in contact with a concave lens of power -4 D. What is the power of combination and nature of lens combination ?

Explanation

To solve the problem of finding the power of the combination of a convex lens and a concave lens placed in contact, we can follow these steps:

### Step 1: Identify the powers of the individual lenses
- The power of the convex lens (P1) is given as +5 D (diopters).
- The power of the concave lens (P2) is given as -4 D (diopters).

### Step 2: Use the formula for the power of the combination of lenses
The total power (P) of a combination of lenses in contact is given by the sum of the individual powers:
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