A student of height 1.9 m can see his full image in a plane mirror fixed on a wall. His eyes are 1.85 m from the floor level. What is the minimum length of the plane mirror required to get the full image of the student ?

Options

A. 0.85 m
B. 0.75 m
C. 0.95 m
D. 0.8 m

Explanation

To find the minimum length of the plane mirror required for the student to see his full image, we can follow these steps:

### Step 1: Understand the relationship between the height of the person and the mirror
The height of the mirror required to see the full image of a person is half the height of the person. This is due to the way light reflects in a plane mirror. The image formed is as tall as the object, but the mirror only needs to be half the height of the object for the entire image to be visible.

### Step 2: Calculate the height of the student
The height of the student is given as:
- Height of the student (h) = 1.9 m

### Step 3: Calculate the minimum length of the mirror
To find the minimum length of the mirror (L), we can use the formula:
\[ L = \frac{h}{2} \]
Substituting the height of the student into the equation:
\[ L = \frac{1.9 \, \text{m}}{2} = 0.95 \, \text{m} \]

### Step 4: Conclusion
The minimum length of the plane mirror required for the student to see his full image is:
\[ L = 0.95 \, \text{m} \]

### Final Answer:
**The minimum length of the plane mirror required is 0.95 m.**

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