The maximum magnification that can be obtained with a convex lens of focal length 2.5 cm is (the least distance of distinct vision is 25 cm )

Options

A. 10
B. `0.1`
C. `62.5`
D. 11

Answer

To find the maximum magnification that can be obtained with a convex lens of focal length 2.5 cm, we can use the formula for magnification (M) given by:

\[ M = 1 + \frac{D}{F} \]

where:
- \( D \) is the least distance of distinct vision (25 cm),
- \( F \) is the focal length of the lens (2.5 cm).

### Step-by-Step Solution:

1. **Identify the given values**:
- Focal length \( F = 2.5 \) cm
- Least distance of distinct vision \( D = 25 \) cm

2. **Substitute the values into the magnification formula**:
\[ M = 1 + \frac{D}{F} \]
Substituting the values:
\[ M = 1 + \frac{25}{2.5} \]

3. **Calculate \( \frac{D}{F} \)**:
\[ \frac{25}{2.5} = 10 \]

4. **Add 1 to the result**:
\[ M = 1 + 10 = 11 \]

5. **Conclusion**:
The maximum magnification that can be obtained with the given convex lens is \( M = 11 \).

### Final Answer:
The maximum magnification is **11**.

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