The image formed in a periscope is virtual without lateral inversion because 2 lateral inversions cancel each other.
What is periscope?
A periscope is defined as an instrument used for observing over, around or through an obstacle or object, which is prevented by direct line of sight. It consists of an outer case with mirrors at each end at a 45° angle. These mirrors are placed parallel to the surface.
The image developed by a plane mirror is virtual and laterally inverted. When a ray reflected by the 1st mirror shifts the incident ray for the 2nd one, this laterally inverted incident ray gets reflected by the 2nd mirror. It results in a virtual image without lateral inversion. The image formed in a periscope is virtual without lateral inversion because 2 lateral inversions cancel each other.
Hence, the image formed in a periscope is virtual without lateral inversion.
Applications Of Periscope
Other than observing objects that are not in the direct line of sight, the following are various other uses of periscope:
- Used in submarines to determine the distance of a torpedo and helps in deciding the right time for the attack.
- Used in a nuclear reactor to observe the chemical reactions that are taking place.
- In the military, periscopes are used to observe from their hiding position.