1.

A glass slab consists of thin uniform layers of progressively decreasing refractive indices [Fig. 2.95] such that the refractive index of any layer is mu - m Delta mu . Here mu and Delta mu denote the refractive index of the 0 th layer and the difference in refractive index between any two consecutive layers respectively. The integerm = 0,1,2,3 cdots denotes the numbers of the successive layers. A rays light from the 0 th layer enters the 1 st layer at an angle of incidence of 30^(@). After undergoing the m th refraction, the ray emerges parallel to the interface. If mu = 1.5 and Deltamu - 0.015 the value of m is

Answer»

20
30
40
50

Solution :From Snell.s LAW, we have, for n number of media,
`mu_(1)sini_(1) = mu_(2) sini_(2) = mu_(n)sin_(n)`
`therefore " " musin30^(@) = (mu - mDeltamu)sin90^(@)`
`or, 1.5 sin30^(@) = (1.5 - m XX 0.015) xx 1 or, 0.015m = (3)/(4)`
`therefore " " m = (3)/(4) xx (1000)/(15) = 50`


Discussion

No Comment Found

Related InterviewSolutions