Refraction: Reflection after passing the critical angle

[rishch]

If the angle of incidence is greater than the critical angle then it is reflected back into same medium. Is this reflection normal reflection? (as in it obeys all the rules of reflection, like reflection in mirrors) Or is it a bit different?

 

[rishch]

And also, in my book, under total reflection prisms, they've given the advantages of total reflection prisms as-

The reflection efficiency is nearly 100% as against an ordinary plane mirror whose reflectivity is poor.

There is is no problem of multiple reflections in the case of prisms while this problem spoils the quality of images in mirrors.

How can a plane mirror have poor reflectivity? What happens to the light that is not reflected? I thought mirrors reflected all the light.

And what do they mean by multiple reflection?

 

[K^2]

Total internal reflection follows normal reflection rules.

Mirror absorbs a portion of the light. It also reflects both at the front glass surface and the back surface, that's the multiple-reflection problem the book mentions. Light reflected from the back surface might be reflected back into the mirror again by the front surface, and so on. This will contribute to the absorption losses as well.

 

[rishch]

By front surface you mean the surface of the glass and by back portion you mean the silver reflecting surface on the back right? Oh and what are co axial rays? (Sorry for adding questions every post)

 

[sardar]

This type of reflection is known as total internal reflection and it follows the same rules as normal reflection, such as the law of reflection. However, it is different in that it occurs when light passes from a medium with a higher refractive index to a medium with a lower refractive index, and the angle of incidence is greater than the critical angle. This results in all of the light being reflected back into the original medium instead of being transmitted through the second medium. This phenomenon is commonly observed in situations such as mirages and fiber optics. So while it follows the same principles as normal reflection, it is a unique type of reflection that occurs under specific conditions.