## A Question from Optics

In method of determining refractive index of transparent liquid with help of convex lens and plane mirror ,an equi double convex lens of refractive index 1.5 has been taken…. Sir plzzzz tell what is the relation for refractive index of liquid of convex lens and that of combination   Can you answer?

## Why Rainbow is in the form of an arc?

Why is a rainbow always bent in the shape of a semi circle…?? but according to the theory light travels straight….!!! (Ramesh asked)

## A Numerical from Combination of thin lenses in contact

Two thin lenses of focal lengths f1=20cm and f2=60cm are placed in contact. find the focal length f3 of the combined lenses. find also the focal length f of a third lens placed in contact with these two that would result in overall focal length f11=-40cm. (Asked Young)
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## What accounts for the acceleration or deceleration of light when it travels from one medium to another?

“When light passes through different mediums speed changes but who provide acceleration to change velocity?” This question was posted by Jishnu Answer: Just imagine you are participating in a cross country race. When the road is good you can travel faster; but if the path is a marshy place, your speed will decrease. This is …Read the full post

## Light Glossary

additive color A primary light color—red, blue, or green; these three colors produce white light when added together. angle of incidence The angle between a wave striking a barrier and the line perpendicular to the surface. angle of reflection The angle between a reflected wave and the normal to the barrier from which it is…… Continue reading Light Glossary

## Introduction to Light – NASA

Light is a form of radiant energy or energy that travels in waves. Since Greek times, scientists have  debated the nature of light. Physicists now recognize that light sometimes behaves like waves and, at other times, like particles. When moving from place to place, light acts like a system of waves. In empty space, light…… Continue reading Introduction to Light – NASA

## Question from Wave Optics

Rajat Asked: What is the difference between interference and diffraction? Ans: Interference is caused by the superposition of wave fronts from two coherent sources; But diffraction is caused by the superposition of wavelets from a single wavefront when it confronts an obstacle or a slit. Note: Visitors are requested to add to the answer through…… Continue reading Question from Wave Optics