A ray of light travelling in air enters obliquely into water .The angle of refraction will be *
a) equal to the angle of incidence
b) greater than the angle of incidence
c) smaller than the angle of incidence
d) equal to zero
Answers
Answer:
Explanation:
When a ray of light travels from air into water obliquely, it bends towards the normal. This is because water is optically denser than air. On entering water, speed of light decreases and the light bends towards normal.
Answer:
The diagram below shows a light ray undergoing refraction as it passes from air into water. The incident ray is a ray (drawn perpendicular to the wavefronts) that shows the direction that light travels as it approaches the boundary. Similarly, the refracted ray is a ray (drawn perpendicular to the wavefronts) that shows the direction that light travels after it has crossed over the boundary. In the diagram, a normal line is drawn to the surface at the point of incidence. This line is always drawn perpendicular to the boundary. The angle that the incident ray makes with the normal line is referred to as the angle of incidence. Similarly, the angle that the refracted ray makes with the normal line is referred to as the angle of refraction.
The cause of refraction is a change in light speed; and wherever the light speed changes most, the refraction is greatest. The speed is related to the optical density of a material that is related to the index of refraction of a material. Air is the least dense material (lowest index of refraction value) and water is the denser material (largest index of refraction value). Thus, it would be reasonable that the most refraction occurs for the transmission of light across an air-water boundary.
Hence, the angle of refraction will be smaller than the angle of incidence