This means that a lot of the blue light has been scattered out well before the light arrives at us, so the sky appears redder.Ĭlouds appear white because the water droplets are much larger than the wavelengths of light. This is similar to the question: “Why are sunsets red?” When the Sun appears lower in the sky, the light that reaches us has already travelled through a lot more of the atmosphere. When we look at the sky, we see all the places that the blue light has been scattered from. Blue light has a smaller wavelength than red light, so it is scattered much more than red light. Point Source (a): All light rays originate at a point and radially diverge. A rendering method uses intensity calculations from the illumination model to determine the light intensity at all pixels in the image.

As this light hits the particles of nitrogen and oxygen in our atmosphere, it is scattered in all directions. An illumination model is used to calculate the intensity of the light that is reflected at a given point on a surface. Light from the sun is made of all the colours of the rainbow. “Why is the sky blue?” is a common question. The amount of scattering depends on how big the particle is compared to the wavelength of light that is hitting it. Fresnel formulas for metals: For the calculation of the wave reflected. Some light is scattered in all directions when it hits very small particles such as gas molecules or much larger particles such as dust or droplets of water. The transmitted intensity, including the back and forth reflected light is given by. If imaginary lines are traced back, they appear to come from a focal point behind the mirror.Ĭonvex mirrors are useful for shop security and rear-view mirrors on vehicles because they give a wider field of vision. German astronomer Johannes Kepler discussed the inverse-square law and how it affects the intensity of light. Parallel rays of light strike the mirror and are reflected outwards. The inside curve of a spoon is an example of a concave mirror It is possible to make mirrors that behave like humps or troughs, and because of the different way they reflect light, they can be very useful. This is because the reflecting surface is no longer flat and may have humps and troughs caused by the wind. However, if there are ripples or waves in the water, the reflection becomes distorted. When the water in a lake or sea is very still, the reflection of the landscape is perfect, because the reflecting surface is very flat.

With a flat mirror, it is easy to show that the angle of reflection is the same as the angle of incidence. If you measure the angle of incidence and the angle of reflection against the normal, the angle of incidence is exactly the same as the angle of reflection. If you want to measure these angles, imagine a perfectly straight line at a right angle to the reflective surface (this imaginary line is called ‘normal’).

Intensity of reflected light equation