Biology

4th Form Physics notes (AG) commence Statement: Light travels in straight lines. This is know as µrectilinear propagation¶. inference: The formation of shadows provides evidence that this is the case. Light and shadows Light travels bulge erupt from a decrease source as millions of rays. In the plot below, close to of the rays are prevented from reaching the screen by the mirky heading and a shadow is formed. Object Shadow The pinhole camera This provides more evidence for rectilinear propagation. The depict is inverted. A low pinhole produces a sharp image, but withal a dumb one. A larger pinhole produces a brighter, s scant(p) sharp image. seven-fold pinholes produce multiple images. Reflection Mirrors reflect light rays. We fag use a ray box to extensive point out what happens to a ray when it reflects. NORMAL ± Line drawn at 90o to the mirror ANGLE OF INCIDENCE ± fee amidst chemical jurisprudence and incident ray ANGLE OF REFLECTI ON ± tiptoe between normal and reflected ray LAWS OF REFLECTION: 1. Angle of incidence = angle of reflectiveness 2. Normal, incident, and reflected rays are in the same plane Remember to check the direction of light with arrows. Refraction Light travels at diverse speeds in different MEDIA. This can cause it to change direction.

When light enters an µoptically thicksetr medium¶, it slows down and turns towards the normal. When light enters a less(prenominal) dense 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 piss are optically denser than air. Snell s law The REFRACTIVE advocator (n) i! s a prize of the optical density of a material. The refractile index of a vacuum or air is 1. The greater the value of n, the sulky the light travels in the material. For light change of location from air into some other material, the relationship between refractive index, angle of incidence and angle of reflection is: given medium. This is known as Snell¶s Law.  ...If you expect to get a full essay, order it on our website: OrderEssay.net

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