Two plane mirrors are placed making an angle θ in between them. What is the expression for the number of images formed of an object placed between the mirrors?

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n if

n = \frac{360}{\emptyset}

is odd and the object is asymmetrically placed.

n – 1 if

n = \frac{360}{\emptyset}

is even, or odd and the object is symmetrically placed.

Both A and B.

None of these

answer is C.

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Detailed Solution

Concept: When an object's image is viewed through two inclined plane mirrors, more than one image is created. The number of images produced is determined by the angle between the two mirrors.
The formula below calculates the number of pictures created by two flat mirrors inclined at an angle A to each other.
Number of images n=

\frac{360}{A} - 1

The number of images formed n=

\frac{360}{A} - 1

, if

\frac{360}{A}

is an even integer.
If

\frac{360}{A}

is a fraction, the number of images formed is equal to its integral part. As the angle gets smaller (down to 0 degrees when the mirrors are facing each other and parallel) the smaller the angle the greater the number of images.
Hence, option 3 is correct.

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