Waves

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Carries audio for T.V. Broadcasts

Longer wavelength so can bend around hills

FM – frequency modulation

Carries video for T.V. Broadcasts

© 2000 Microsoft Clip Gallery

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Short Wavelength Microwave

Invisible Spectrum (Cont.)

Infrared Rays

Def – Light rays with longer wavelength than red light.

Uses: Cooking, Medicine, T.V. remote controls

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Electromagnetic Spectrum

Invisible spectrum (cont.).

Ultraviolet rays.

Def. – EM waves with frequencies slightly higher than visible light

Uses: food processing & hospitals to kill germs’ cells

Helps your body use vitamin D.

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Electromagnetic Spectrum

Invisible Spectrum (Cont.)

X-Rays

Def. - EM waves that are shorter than UV rays.

Uses: Medicine – Bones absorb x-rays; soft tissue does not.

Lead absorbs X-rays.

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Electromagnetic Spectrum

Invisible spectrum (cont.)

Gamma rays

Def. Highest frequency EM waves; Shortest wavelength. They come from outer space.

Uses: cancer treatment.

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Light: Particles or Waves?

Wave Model of Light

Explains most properties of light

Particle Theory of Light

Photoelectric Effect – Photons of light produce free electrons

© 2000 Microsoft Clip Gallery

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Light: Refraction of Light

Refraction – Bending of light due to a change in speed.

Index of Refraction – Amount by which a material refracts light.

Prisms – Glass that bends light. Different frequencies are bent different amounts & light is broken out into different colors.

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Refraction (Cont.)

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Refraction-Spectroscope Lab

Hey girls! The filters go on the Spectroscope, not on the lashes!

© 2000 D. L. Power

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Color of Light

Transparent Objects:

Light transmitted because of no scattering

Color transmitted is color you see. All other colors are absorbed.

Translucent:

Light is scattered and transmitted some.

Opaque:

Light is either reflected or absorbed.

Color of opaque objects is color it reflects.

© 2000 Microsoft Clip Gallery

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