Question

The absolute refractive indices of glass and water are \(\frac {3}{2}\) and \(\frac {4}{3}\). Determine the ratio of the speeds of light in glass and water.

(a) 5:7

(b) 9:8

(c) 7:5

(d) 8:9

I had been asked this question in unit test.

This question is from Wave Optics topic in portion Wave Optics of Physics – Class 12

Answer 1

Right answer is (d) 8:9

Easiest explanation: \( \frac {v_g}{v_w} = \frac {\mu_w}{\mu_g}\)

\(\frac {v_g}{v_w} = \frac {(\frac {4}{3} )}{(\frac {3}{2}) }\)

\(\frac {v_g}{v_w}\) = 8:9