Question

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

• A. 1.5
• B. 1.6
• C. 1.7
• D. 1.8

Answer 1

Answer: (A)

1.5

Answer 2

$\delta = i + e - A$
$40 = 35 + 79 - A$
$40 = 114 - A$
$A = 114 - 40 = 74 = r_1 + r_2$
From this we get,
$\mu = 1.5$
$\therefore \, \, \delta_{min} < 40^{\circ}$
$\mu < \frac{\sin \left(\frac{70 + 40}{2} \right)}{\sin 37}$
$\therefore \, \, \mu_{max} = 1.44$