5AM vs FM radioFrequency ModulatedAmplitude Modulated
6Both AM & FM radio signals have advantages and disadvantages. Generally, AM waves have much longer wavelengths than FM waves and can DIFFRACT better than FM waves and can travel greater distances before the signal fades. FM is more direct line of sight.However, because information is coded in the amplitude of an AM wave, power lines and lightning can influence the amplitude and are more likely to interfere with the AM wave.FM has a greater range of frequency which is better for music whereas AM is better for talk radio since there isn’t much fluctuation in a person’s voice.
19With diffuse reflection, your eye sees reflected light at all angles With diffuse reflection, your eye sees reflected light at all angles. With specular reflection (from a mirror), your eye must be in the correct position.
20Refraction of LightWhen a ray of light enters a different medium at an angle other than 0o with the normal, it will bend or REFRACT due to a speed change due to material change.20
24A ray of light is incident on the surface of a block of clear ice (1 A ray of light is incident on the surface of a block of clear ice (1.309) at an angle of 40.0° with the normal. Part of the light is reflected and part is refracted. Find the angle between the reflected and refracted light.24
26b) its frequency in zircon c) its wavelength in zircon. The light emitted by a helium–neon laser has a wavelength of 632.8nm in air. As the light travels from air into zircon (1.923), finda) its speed in zirconb) its frequency in zirconc) its wavelength in zircon.26
38Observing the RainbowIf a raindrop high in the sky is observed, the red ray is seenA drop lower in the sky would direct violet light to the observerThe other colors of the spectra lie in between the red and the violet38
39A bright underwater flood light at the bottom of a 2 A bright underwater flood light at the bottom of a 2.75-m deep pool is positioned 1.85 m from one edge of the pool. At what angle will light emerge from the surface of the water at the edge of the pool. Assume the pool is filled to the brim with water.39
42Image characteristics: TYPE –B) ORIENTATIONC) MAGNIFICATION (M)D) Position & height of image and object42
43Reflection & Image Formation by a Plane Mirror What you see when you look into a plane (flat) mirror is an image, which appears to be behind the mirror.
44Properties of the Image Formed by a Plane/Flat Mirror 44
45Concave MirrorConverges light rays after reflection45
46Parallel light rays reflecting off of concave mirror Note how all 4 rays reflect and converge at common point. This is called FOCAL POINT.46
47Focal LengthIncoming rays are parallel and all reflect through a common point called the FOCAL POINT, F.47
48Applications of concave mirror PARABOLIC REFLECTORS -Behind flashlight bulbs, headlights, searchlights. projects light out in a concentrated beam…bulb is placed at focal pt.SATELLITE DISH -Microwaves strike dish and reflect and collect at the receiver (at focal point)SOLAR COOKERMAKEUP MIRROR…provides an enlarged image of face when held close to face48
49Convex MirrorDiverges light rays after reflection49
65Sign convention for lenses Where you expect light to end up is assumed positive (opposite side of lens)Converging lenses have +fDiverging lenses have -f
66ExampleBased on the picture shown, describe the type of lens and the type of imageIf the magnifying glass was immersed in water, what effect (if any) would that have on parallel rays leaving the lens?66
67APPLICATIONS OF LENSES Overhead projector (lens + mirror), eyeglasses, contacts, magnifying glass, telescopes, microscopes, your eye, etc67
69The ability of the eye to instantly adjust its focal length is known as accommodation. Your ciliary muscles flex and manipulate the curvature and shape of your lens which changes the focal length of the lens.69
72Astigmatism means that the cornea is oval like a football instead of spherical like a basketball. This causes light to focus on more than one point in the eye, resulting in blurred vision at a distance or near.72
74Combination of Thin Lenses The image produced by the first lens is calculated as though the second lens were not presentThe light then approaches the second lens as if it had come from the image of the first lensThe image of the first lens is treated as the object of the second lensThe image formed by the second lens is the final image of the system74
75ExampleAn object is located 4.75m from a simple optical system consisting of two converging lenses. The first lens of this system has a focal length of 100 mm and the second lens, which is 20.0 cm from the first lens, has a focal length of mm. What is the magnification of the system?75
76Example 2An object is placed 20.0 cm to the left of a converging lens of focal length 25.0 cm. A diverging lens of focal length 10.0 cm is 25.0 cm to the right of the converging lens. Find the position and magnification of the final image.76