Which one of the folowing phenomena verifies the fact that light travels much faster than sound?

Which of the following does not change when light travels from one medium to another?

Which one of the following phenomenon is used in optical fibres?

Which one of the following statements is not correct for light rays ?

Which of the following are the primary colours of light?

Light waves are incident on an air-glass boundary. Some of the light waves are reflected and some are refracted in the glass. Which one of the following properties is the same for the incident wave a…