Periscope works on the principle of:

• A. refraction of light
• B. reflection of light
• C. diffraction of light
• D. scattering of light

To understand how a periscope functions, we need to look at the principles of light behavior. The correct answer to your question is B: reflection of light. Let’s break this down to see why reflection is the key principle at play in a periscope.

The Basics of a Periscope

A periscope is an optical instrument that allows an observer to see over or around an obstacle. It is commonly used in submarines and by military personnel. The design typically consists of two mirrors positioned at 45-degree angles to each other and a tube that connects them.

How Reflection Works in a Periscope

When light travels, it can interact with surfaces in different ways. In the case of a periscope, light enters through the top of the tube and strikes the first mirror. Here’s how the process unfolds:

• Light Entry: Light from the object you want to see enters the periscope.
• First Reflection: The light hits the first mirror at a 45-degree angle. According to the law of reflection, the angle of incidence equals the angle of reflection. This means the light reflects off the mirror and travels down the tube.
• Second Reflection: The light then reaches the second mirror, which is also positioned at a 45-degree angle. It reflects again, this time directing the light towards your eyes.

Why Not Other Principles?

Now, let’s consider why the other options—refraction, diffraction, and scattering—are not applicable here:

• Refraction: This involves the bending of light as it passes through different mediums, like air to water. A periscope does not rely on this bending effect.
• Diffraction: This is the spreading of light waves when they encounter an obstacle or aperture. While diffraction can affect how light behaves, it is not the primary mechanism in a periscope.
• Scattering: This occurs when light is forced to deviate from a straight path due to particles in the medium. Again, this is not how a periscope operates.

Real-World Application

In practical terms, the use of reflection in a periscope allows for a simple yet effective way to observe objects that are not directly visible. For example, submarines can use periscopes to see above the water while remaining submerged, keeping them hidden from view.

In summary, the principle of reflection is fundamental to the operation of a periscope, enabling it to function effectively in various scenarios. Understanding this principle not only clarifies how periscopes work but also provides insight into the broader applications of optics in technology and everyday life.