Q. The optical fibres have an inner core of refractive index and a cladding of refractive index such that

 2240  200 KEAMKEAM 2007Ray Optics and Optical Instruments Report Error

Solution:

Optical fibre is made of a thin glass core (diameter 10 to ) surrounded by a glass coating called cladding is protected by a jacket of plastic. The refractive index of the glass used for making core is a little more than the refractive index of the glass used for making the cladding ie, .