Laws of Reflection and Refraction Reflection When an EM wave strikes a surface, it can be either reflected back or transmitted into the material beyond t...
Reflection
When an EM wave strikes a surface, it can be either reflected back or transmitted into the material beyond the surface. The laws of reflection are simple and tell us how the angle of reflection and the angle of incidence relate to each other.
** Snell's Law** states that the ratio of the sine of the angle of incidence to the sine of the angle of reflection is equal to the ratio of the speeds of light in the two materials. This law applies to both reflected and refracted waves and is a powerful tool for understanding how light interacts with different materials.
Refraction
When light passes from a medium with a higher refractive index (n_i) to a medium with a lower refractive index (n_r), it bends or refracts away from the normal. This bending of light can cause the light to exit the material at an angle greater than the angle of incidence.
The amount of bending depends on the differences in the speeds of light in the two materials. The higher the refractive index of a medium, the greater the amount of bending that occurs.
Refraction formulas:
Incident angle (θi): The angle between the incident ray and the normal at the point of incidence.
Reflected angle (θr): The angle between the reflected ray and the normal at the point of incidence.
Refractive index (n): A measure of how a medium bends light. It is equal to the ratio of the speed of light in vacuum to the speed of light in the medium.
Normal (n_i): The angle between the surface normal and the incident ray.
Normal (n_r): The angle between the surface normal and the refracted ray.
By understanding these laws, we can predict how light will behave when it interacts with different materials and can design optical devices such as lenses, mirrors, and prisms