Respuesta :

When light is passing from a denser medium to a lighter medium ( for example: from water to air) 
 When the angle of refraction is greater than the critical angle( angle of incidence when the angle of refraction is perpendicular to the normal) of the denser medium.

Answer:

light passing from a low-velocity medium to a high-velocity medium at an incident angle larger than the critical angle will be totally reflected.

Explanation: