Total internal reflection (TIR) occurs when light enounters a surface between two materials at an angle of incidence greater than a certain critical angle. When TIR occurs, all of the light is reflected and none of it can cross the surface into the other material.
TIR only happens when the light tries to enter a material in which the speed of light is HIGHER. It happens, for example, inside glass fiber optics. All of the light stays inside the glass until it comes out the other end.
Could you please explain "total internal reflection" in simple terms (suitable for a 12/13 yr old.
2 answers
This is hard to explain without a diagram.
Imagine that we have a boundary between two materials. This could be say the edge between glass and air, or between plastic and water, or between two solids say perspex and glass. Each of these pairs have a differencet refractive index, i.e. bends light through different angles.
When light crosses the boundary between the two materials with different refractive indices, the light beam will be refracted at the boundary between the two. However, if the angle of approach (incidence) is close to being parallel to the boundary then the light is refracted so that it travels along the boundary and the light will stop crossing the boundary altogether. The angle where this happens is called the critical angle. If the angle is greater than the critical angle the light is reflected back and this is total internal reflection.
It is worth remembering that this
only occurs where light travels from a medium with a higher refractive index to one with a lower refractive index. For example, it will occur when passing from glass to air, but not when passing from air to glass.
There is a good diagram at
(Broken Link Removed)
also
http://www.fiberoptics4sale.com/Merchant2/fofs_img/total-internal-reflection.gif
Any help?
Imagine that we have a boundary between two materials. This could be say the edge between glass and air, or between plastic and water, or between two solids say perspex and glass. Each of these pairs have a differencet refractive index, i.e. bends light through different angles.
When light crosses the boundary between the two materials with different refractive indices, the light beam will be refracted at the boundary between the two. However, if the angle of approach (incidence) is close to being parallel to the boundary then the light is refracted so that it travels along the boundary and the light will stop crossing the boundary altogether. The angle where this happens is called the critical angle. If the angle is greater than the critical angle the light is reflected back and this is total internal reflection.
It is worth remembering that this
only occurs where light travels from a medium with a higher refractive index to one with a lower refractive index. For example, it will occur when passing from glass to air, but not when passing from air to glass.
There is a good diagram at
(Broken Link Removed)
also
http://www.fiberoptics4sale.com/Merchant2/fofs_img/total-internal-reflection.gif
Any help?
1 answer