1.

If the critical angle for total internal reflection from a medium to vacuum is 30^@, then velocity of light in the medium is .......... ms^(-1). (c = 3.8 xx 10^8 ms^(-1))

Answer»

`3.0xx10^8`
`2.0 XX 10^8`
`1.5 xx 10^8`
`10^(-8)`

SOLUTION :If C is CRITICAL angle then
`n=(1)/(sinC)impliessinC=1/n`…........(1)
but `n=c/v` (where v is the velocity in medium)
`therefore 1/n=v/C` …........(2)
From equation (1) and (2),
`sinC=v/C`
`thereforev=sinCxxc`
`(c=3xx10^8,` critical angle C=`30^@`)
`=sin(30^@)xx3xx10^8=1.5xx10^8" "m//s`


Discussion

No Comment Found

Related InterviewSolutions