Question

Is snell's law applicable in the case of TIR (Total Internal Reflection)

Explain with diagrams ? ​

Answer 1

Yes, Snell's law is applicable for Total Internal Reflection

The two conditions which has to be followed in Total Internal Reflection is  

• The light must ᴘᴀꜱꜱ from the denser medium to a rarer medium

• The angle of incidence must be greater than the critical angle

When angle of incidence is less than the critical angle :

$\sf{\displaystyle n=\frac{n_{r}}{n_{i}}=\frac{\sin i}{\sin r}\:\:(\textsf{snells } \textsf{ law})}$

$\longrightarrow$ Where $\sf{i<r<90^{\circ}}$ and n = refractive index of the denser medium with respect to rarer medium

When angle of incidence is equal to the critical angle :

• The refracted angle will be 90°

$\sf{\displaystyle n=\frac{\sin i_{c}}{\sin 90}}\implies\sf{\displaystyle n=\frac{\sin i_{c}}{1}}\implies\sf{\displaystyle n=\sin i_{c}}$

When angle of incidence is greater than the critical angle, total internal reflection takes place as and Snell's law is valid here also . Snell's law is valid at each and every point of the phenomenon of refraction as it is derived from the Maxwell's equation.

Answer 2

Answer:

Yes, Snell's law is applicable for Total Internal Reflection

Yes, Snell's law is applicable for Total Internal ReflectionThe two conditions which has to be followed in Total Internal Reflection is

index of the denser medium with respect to rarer mediumWhen angle of incidence is equal to the critical angle :The refracted angle will be 90°

⟹n= 1sini c ⟹n=sini c

When angle of incidence is greater than the critical angle, total internal reflection takes place as and Snell's law is valid here also . Snell's law is valid at each and every point of the phenomenon of refraction as it is derived from the Maxwell's equation.