Understanding reflection and refraction are an integral part of school and college learning. In nature even birds and fish (Archer fish) very skillfully use refraction to strike down prey present above or below the water surface. Fermat's principle allows one to look beyond the reasons behind the laws governing the reflection and refraction. A…

A method has been developed to measure the swing period of a simple pendulum automatically. The pendulum position is converted into a signal frequency by employing a simple electronic circuit that detects the intensity of infrared light reflected by the pendulum. The signal produced by the electronic circuit is sent to the microphone port and…

A new procedure for performing quantitative measurements in teaching optics is presented. Application of the procedure to accurately measure the rate of change of the variable refractive index of a water-denatured alcohol mixture is described. The procedure can also be usefully exploited for measuring the constant refractive index of distilled…