Case Study:

Ravi visits a local barber shop in his town for a haircut before his school function. The barber’s shop has a large mirror fixed on the wall in front of the customer. Behind the customer, another mirror is placed so that the barber can show the back side of the haircut.

When Ravi sits on the chair, he notices that he can see both the front and the back of his head through the mirrors. The barber explains that the mirror in front is a plane mirror, which forms an upright image of Ravi’s face. The second mirror behind him reflects the image again, allowing Ravi to see the back of his head.

The distance between Ravi and the front mirror is about 1 meter. According to the laws of reflection in a plane mirror, the image formed appears at the same distance behind the mirror as the object is in front of it.

Thus, Ravi’s image appears 1 meter behind the mirror, making the distance between Ravi and his image 2 meters.

The barber uses this arrangement to carefully check whether both sides of the haircut are equal. By slightly adjusting the angle between the mirrors, he can give Ravi a clear view of the haircut from multiple sides.

This simple setup used in everyday barber shops demonstrates the properties of plane mirrors, such as upright images, equal image distance, lateral inversion, and multiple reflections.

Mirrors used in barber shops help barbers clearly see different angles while cutting hair. This setup works because of the laws of reflection and image formation in mirrors.
If you want to understand the basic concepts first, read these topics

Questions

Section A - MCQs

1. Ravi sits 1 m away from the mirror in the barber shop. The image of Ravi will appear at a distance of:

A. 0.5 m behind the mirror
B. 1 m behind the mirror
C. 2 m behind the mirror
D. 3 m behind the mirror

2. The total distance between Ravi and his image in the mirror is:

A. 1 m
B. 2 m
C. 3 m
D. 4 m

3. The mirror commonly used in barber shops is:

A. Concave mirror
B. Convex mirror
C. Plane mirror
D. Spherical mirror

4. When Ravi raises his right hand, the image appears to raise the left hand. This phenomenon is called:

A. Reflection
B. Refraction
C. Lateral inversion
D. Image distortion

Section B - Short Answer Questions

1. Explain why a barber places another mirror behind the customer in the shop.

2. Ravi stands 80 cm away from a plane mirror. At what distance behind the mirror will his image be formed? Also calculate the distance between Ravi and his image.

3. Why is a plane mirror preferred in barber shops instead of a concave or convex mirror?

Section C - Long Answer Question

1. A barber places two plane mirrors facing each other in his shop so that customers can see different angles of their haircut.

a) Explain how multiple reflections occur in this arrangement.
b) What will happen if the angle between the mirrors is slightly changed?
c) Suggest two other real-life situations where multiple reflections using mirrors are useful.

Answer Key

MCQ Answers

1. 1. B - 1 m behind the mirror
2. 2. B - 2 m
3. 3. C - Plane mirror
4. 4. C - Lateral inversion

Short Answer Solutions

1. The second mirror reflects the image formed by the first mirror. This allows the customer to see the back of the head, which cannot be seen directly in the front mirror.

2. Object distance = 80 cm

For a plane mirror:
Image distance = Object distance

Image distance = 80 cm behind the mirror

Distance between object and image =
80 cm + 80 cm = 160 cm (1.6 m)

3. A plane mirror is used because it forms an upright image of the same size as the object, which helps the barber see the haircut accurately. Concave or convex mirrors would produce distorted or magnified images.

Long Answer Solution

a) When two plane mirrors face each other, light rays reflect repeatedly between them. This produces multiple images due to continuous reflections.

b) If the angle between the mirrors changes, the number and positions of images change. Smaller angles generally produce more images.

c) Examples of multiple reflections:

• Dressing mirrors in clothing stores
• Kaleidoscopes used in toys and optical devices