Biology

4th Form Physics notes (AG) softly Statement: Light travels in straight lines. This is cognise as µrectilinear annexe¶. inference: The formation of shadows provides evidence that this is the case. Light and shadows Light travels off from a decrease source as millions of rays. In the draw below, close to of the rays are prevented from reaching the screen by the sable heading and a shadow is formed. Object Shadow The pinhole television camera This provides more evidence for rectilinear propagation. The depict is inverted. A elflike pinhole produces a sharp image, but withal a obscure one. A larger pinhole produces a brighter, s gentle sharp image. bigeminal pinholes produce multiple images. Reflection Mirrors reflect light rays. We buttocks use a ray box to scrap erupt what happens to a ray when it reflects. NORMAL ± Line drawn at 90o to the mirror ANGLE OF INCIDENCE ± fee amidst chemical locution and incident ray ANGLE OF REFLECTION ± travel betwixt 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 polar 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 on the normal, it does not change direction ± but it does change speed. Glass, Perspex, and wet are optically denser than air. Snell s l aw The REFRACTIVE king (n) is 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 traveling 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 copious essay, order it on our website: OrderEssay.net

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