The correct option is (c).
Explanation
When two plane mirrors are inclined at an angle $\theta$ to each other, multiple images are formed due to successive reflections of light rays between the mirrors. The number of images ($n$) formed is governed by the relationship between $360^{\circ}$ and the angle of inclination $\theta$.
Statement-wise Analysis:
- Statement 1 is Incorrect. When two mirrors are placed parallel to each other, the angle between them is $0^{\circ}$ ($\theta = 0^{\circ}$). According to the formula, the number of images would approach infinity. Practically, a large number of images are formed in a sequence (like in a barber shop), limited only by the intensity of light. Therefore, the number of images is infinite, not finite.
- Statement 2 is Correct. When two mirrors are placed at right angles ($\theta = 90^{\circ}$), the number of images formed is calculated as:
$n = \frac{360^{\circ}}{90^{\circ}} - 1 = 4 - 1 = 3$.
Since 3 images are formed, the statement that "multiple images are formed" is factually correct. - Statement 3 is Correct. The number of images formed is directly dependent on the angle $\theta$ between the mirrors. The general formula is $n = \frac{360^{\circ}}{\theta} - 1$ (if $\frac{360^{\circ}}{\theta}$ is an even integer). As the angle changes, the number of images changes.
Key Takeaway:
The number of images ($n$) formed by two plane mirrors inclined at an angle $\theta$ is generally given by $n = \frac{360^{\circ}}{\theta} - 1$. Parallel mirrors ($\theta = 0^{\circ}$) produce infinite images, while inclined mirrors produce a finite number of multiple images depending on the specific angle.