The amount of refraction depends on:
the angle the light hits the boundary between the substances
the difference in relative densities [density: A measure of the quantity of some physical property (usually mass) per unit length, area, or volume (usually volume).] , between the two media (which determines how much the speed of light changes)
The degree to which a material slows the speed of light (compared to its speed in a vacuum) is its refractive index [refractive index: A measurement of the speed at which light passes through a substance, relative to the speed of light in a vacuum. It also indicates how much light will be bent when it passes from one substance into another.] . This can be calculated using the equation:
refractive index = sin i/sin r
i is the angle of incidence
r is the angle of refraction
A beam of light hits a glass block. The angle of incidence [angle of incidence: Angle between the normal and a light ray travelling towards a mirror or into another substance.] angle of incidence is 55°. The angle of refraction [angle of refraction: Angle between the normal and a refracted light ray.] inside the block is 33°. Calculate the refractive index.
A ray of light passing from the air into glass, showing the incident ray (in the air) and the refracted ray (in the glass).
Step 1: Work out the sine of angle i
sin 55 = 0.819
Step 2: Work out the sine of angle r
sin 33 = 0.545
Step 3: Divide sin i by sin r
refractive index = sin i ÷ sin r
refractive index = 0.819 ÷ 0.545 = 1.50
A refractive index of 1.5 will slow down light and bend it toward the normal inside the glass block.
Поразительно, - пробурчал он, - что сотрудникам лаборатории систем безопасности ничего об этом не известно. ГЛАВА 47 - Шифр ценой в миллиард долларов? - усмехнулась Мидж, столкнувшись с Бринкерхоффом в коридоре. - Ничего. - Клянусь, - сказал .