1.

The prism shown in the figure has one side silvered. The angle of the prims is 30^(@) and mu=sqrt(2). What should be the angle of incidence, if the incidence ray retraces its initial path?

Answer»

`50^(@)`
`45^(@)`
`60^(@)`
`75^(@)`

Solution :(B) To retrace the path ray MUST be incident normally on the silvered face of the rism.

In `DeltaAED`
`30^(@)+90^(@)+/_D=180^(@)`
`/_D=60^(@)`
ALSO `/_D+/_r=90^(@)`
`/_r=90^(@)-60^(@)~=30^(@)`
From shell's law
`1 sin i =(sqrt(2))sin 30^(@)`
`i=sin^(-1)(1/(sqrt(2)))`
`i=45^(@)`


Discussion

No Comment Found

Related InterviewSolutions