As we change angle of LASER beam passing through water, the beam suddenly reflects inside water in stead of refracting through transparent water. Can you explain this
Answers
Incident angle > Critical angle
Explanation:
Total internal reflection, in physics, complete reflection of a ray of light within a medium such as water or glass from the surrounding surfaces back into the medium. The phenomenon occurs if the angle of incidence is greater than a certain limiting angle, called the critical angle. In general, total internal reflection takes place at the boundary between two transparent media when a ray of light in a medium of higher index of refraction approaches the other medium at an angle of incidence greater than the critical angle. For a water-air surface the critical angle is 48.5°. Because indices of refraction depend on wavelength, the critical angle (and hence the angle of total internal reflection) will vary slightly with wavelength and, therefore, with colour. At all angles less than the critical angle, both refraction and reflection occur in varying proportions.
When the angle of incidence is more than the critical angle, the rays reflect back from the surface of water as if it is a plain mirror.