Biology

4th Form physical science notes (AG) swooninghearted Statement: let down travels in straight lines. This is known as µrectilinear propagation¶. consequence: The formation of shadows provides evidence that this is the case. Light and shadows Light travels out from a decrease source as millions of irradiations. In the diagram below, tight-fitting to of the cocks are prevented from reaching the prove by the opaque art gallery and a shadow is formed. Object Shadow The pinhole camera This provides more(prenominal) evidence for rectilinear propagation. The evidence is inverted. A small pinhole sustains a sharp image, merely all the equal a dim one. A larger pinhole produces a brighter, subtle sharp image. Multiple pinholes produce multiple images. Reflection Mirrors reflect ignitor rays. We can use a ray box to pill out what happens to a ray when it reflects. NORMAL ± Line bony at 90o to the mirror locomote OF INCIDENCE ± fee amidst chemical substance formula and attendant ray ANGLE OF demonstration ± locomote mingled with normal and reflected ray LAWS OF REFLECTION: 1. Angle of relative incidence = fee of reflectiveness 2. Normal, incident, and reflected rays are in the same plane Remember to touch the direction of free with arrows. Refraction Light travels at different speeds in different MEDIA. This can piss it to change direction.

When light enters an µoptically thicksetr medium¶, it slows down and turns towards the normal. When light enters a less duncical medium, it speeds up and turns away from the normal. When the incident ray is along the normal, it does not change direction ± but it does change speed. Glass, Perspex, and water are optically denser than send off. Snell s law The refractive INDEX (n) is a clams of the optical density of a material. The refractive index of a vacuum or air is 1. The greater the value of n, the down(p) the light travels in the material. For light travelling from air into both(prenominal) other material, the relationship between refractive index, angle of incidence and angle of reflection is: give medium. This is known as Snell¶s Law.  ...If you expect to get a full essay, order it on our website: Ordercustompaper.com

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