Question

Light is going from some denser medium to air The refractive index of the medium is 1.7. Calculate the angle of incidence, such that if it is further increased, Total internal reflection will occur at medium I.

• A. $si{n}^{-1}\left(\frac{1}{\sqrt{3}}\right)$
• B. $si{n}^{-1}\left(\frac{1}{\sqrt{2}}\right)$
• C. $si{n}^{-1}\left(\frac{1}{\sqrt{5}}\right)$
• D. Such an angle of incidence can't be calculated.

Answer 1

The correct option is A $si{n}^{-1}\left(\frac{1}{\sqrt{3}}\right)$


That angle must be the criticle angle.
$\frac{sin\theta }{sin.{90}^{\circ }}=\frac{1}{1.7}$
$\therefore \theta =si{n}^{-1}\left(\frac{1}{\sqrt{3}}\right)$