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 (which is given as 25 cm),
- \( f \) is the focal length of the lens (which is given as 2.5 cm).

Now, let's substitute the values into the formula step by step:

### Step 1: Identify the values
- Least distance of distinct vision, \( d = 25 \) cm
- Focal length of the lens, \( f = 2.5 \) cm

### Step 2: Substitute the values into the magnification formula
Using the formula:
\[ M = 1 + \frac{d}{f} \]
we substitute \( d \) and \( f \):
\[ M = 1 + \frac{25}{2.5} \]

### Step 3: Calculate \( \frac{d}{f} \)
Now, calculate \( \frac{25}{2.5} \):
\[ \frac{25}{2.5} = 10 \]

### Step 4: Add 1 to the result
Now, add 1 to the result from the previous step:
\[ M = 1 + 10 = 11 \]

### Conclusion
Thus, the maximum magnification that can be obtained with the convex lens of focal length 2.5 cm is:
\[ M = 11 \]

### Final Answer
The correct option is 11.

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