Question

Two mrriors are placed at an angle 120⁰ degree to eachother , an object is placed  symmetrically in front of the mirror , find the number of images formed 
1. 5
2. 4
3. 7
4. 2

Answer 1

Correct Answer - Option 4 : 2

CONCEPT: 

• A plane mirror is a planar reflective surface
• The images formed by plane mirror has the following characteristics
  • The image formed is virtual
  • The image formed is erect and the same size as the object
  • The image is laterally inverted and the distance of the object from the plane mirror is the same as that distance of the image from the plane mirror
• The number of images formed between two mirrors placed at an angle θ is given by

number of images = \(\dfrac{360}{θ} - 1\)

Where θ  = Angle

CALCULATION : 

Given  - θ  = 120⁰

The number of images formed is given by

number of images  = \(\frac{360}{120} - 1\)

⇒ number of images  = 3 - 1 = 2 

• The number of images formed is 2.