Two plane mirror are inclined at an angle of `72^@`. The number of images of a point object placed between them will be

Options

A. `8:35`
B. `9:35`
C. `7:35`
D. `8:25`

Answer

To find the number of images formed by two plane mirrors inclined at an angle of \(72^\circ\), we can use the formula for the number of images formed by two mirrors inclined at an angle \(\theta\):

\[ N = \frac{360^\circ}{\theta} - 1 \]

where \(N\) is the number of images and \(\theta\) is the angle between the two mirrors.

### Step-by-Step Solution:

1. **Identify the angle between the mirrors**:
The angle \(\theta\) given in the problem is \(72^\circ\).

2. **Substitute the angle into the formula**:
We will substitute \(\theta\) into the formula:
\[ N = \frac{360^\circ}{72^\circ} - 1 \]

3. **Calculate \( \frac{360^\circ}{72^\circ} \)**:
Performing the division:
\[ \frac{360}{72} = 5 \]

4. **Subtract 1 from the result**:
Now, we subtract 1 from the result:
\[ N = 5 - 1 = 4 \]

5. **Conclusion**:
Therefore, the number of images formed by the two mirrors is \(4\).

### Final Answer:
The number of images of the point object placed between the two mirrors is \(4\).