What is the angle of incidence of a ray if the reflected ray is at an angle of `90^(@)` to the incident ray?

A ray of light from a denser medium strikes a rarer medium at an angle of incidence I (see figure ). The reflected and refracted rays make an angle of 90^(@) with each other. The angles of reflection and refraction are r and r^() . The critical angle is

A ray of light passes from a denser medium to a rarer medium at an angle of incidence i. The reflected and refracted rays make an angle of 90^@ with each other. The angle of reflection and refraction are resepectively r and r'. The critical angle is given by :

A ray of light falls on a glass plate of refractive index mu=1.5 . What is the angle of incidence of the ray if the angle between the reflected and refracted rays is 90^@ ?

A ray of light falls on a plane mirror. When the mirror is turned, about an axis at right angles to the plane of mirror by 20^(@) the angle between the incident ray and new reflected ray is 45^(@) . The angle between the incident ray and original reflected ray was therefore.

If the angle between incident ray and reflected ray is 120^(@) , what is the angle of incidence ?

For which angle of incidence reflected ray is completely polarised?