Concepts of Physics

IIT JEE Physics (1978-2018: 41 Years) Topic-wise Complete Solutions

Rainbow in Water Drops

Objective

To make a rainbow

Introduction

As the light passes through a prism, bending or refraction takes place. The refractive index of prism material is different for different colors. This makes different colors to bend by different angles. This phenomenon is called dispersion.

Apparatus

A sprayer (used by barbers in saloon).

Procedure

In an open place, with sun behind you, spray water in front. Beautiful rainbow appears in the water droplets. For better results, spray water against a dark background.

Discussion

Sunlight first refracts while entering the drop, reflects back from the rear surface of the drop and again refracts while leaving the drop.