Jharkhand PSC Prelim Exam 2006 Solved Paper

(1) Light travels at approximately 300,000 kilometers per second in a vacuum, which has a refractive index of 1.0,but it slows down to 225,000 kilometers per second in water (refractive index = 1.3)and 200,000 kilometers per second in glass (refractive index of 1.5).