Question

Light wave enters from medium $1$ to medium $2$. Its velocity in $2^{nd}$ medium is double from $1^{st}$. For total internal reflection the angle of incidence must be greater than

• A. 30$^{\circ}$
• B. 60$^{\circ}$
• C. 45$^{\circ}$
• D. 90$^{\circ}$

Answer 1

Answer: (A)

30$^{\circ}$

Answer 2

Total internal reflection occurs when theangle of incidence is greater than critical angle (C) in the denser medium. ^{1}\mu_{2}=\frac{Velocity of light in medium ????{Velocity of light in medium ???? $^{1}\mu_{2}=\frac{v}{2v}=\frac{1}{2}.$ Medium ????is denser. or $\quad$ sin $C=\frac{1}{2}$ = sin30$^{\circ}$ or C = 30$^{\circ}.$