In an experiment for determination of refractive index of glass of a prism by `i-delta`, plot it was found thata ray incident at angle `35^circ`, suffers a deviation of `40^circ` and that it emerges at angle `79^circ`. In that case which of the following is closest to the maximum possible value of the refractive index?

Options

A. 1.7
B. 1.8
C. 1.5
D. 1.6

Answer

C

Explanation

We know that `i+e-A=delta`
`35^circ+79^circ-A=40^circ` `:'`A=74^circ`
But `mu=(sin((A+delta_m)/(2)))/((sinA/(2)))=(sin((74+delta_m)/(2)))/(sin((74)/(2)))`
`=(5)/(3)sin(37^circ+(delta_m)/(2))`
`mu_(max)` can be `(5)/(3)`. That is `mu_(max)` is less than `(5)/(3)=1.67`
But `delta_m` will be less than `40^circ` so
`mult(5)/(33)sin57^circlt(5)/(3)sin60^circimpliesmu=1.45`