Light Waves

Find the period of a 10Hz wave -

1/10 or .1

A wave has a frequency of 25Hz and a wave length of 8m, find the speed

200 m/sec

You hear thunder 3 seconds after you see the lightening. How far away is the storm?

3 * 340 m/s (speed of sound) = 1020 meters

Light

A wave that can travel through a vacuum

How electromagnetic waves are classified

According to wavelength and frequency

EM Spectrum

All light, visible and invisible.

Is light a wave or particle.

Both

Gamma Rays

Dangerous EM waves that have very high energy and come from nuclear reactions; can be used to treat some forms of cancer.

X-Rays

EM waves that can pass through skin and have short wavelengths.

Infrared

EM waves that have very low energy and have long wavelengths. The sun emits this.

Ultraviolet

EM waves with more energy than visible light and can cause sunburns.

Infrared

Electromagnetic waves we feel as heat.

Scattering

Interaction of light with matter that causes light to change direction; the reason for the blue sky and why light "dims" over distance.

Why do we see lightening and hear thunder a few seconds later?

Light travels faster then sound, so the light from the lightning hits our eyes before the sound reaches our ears.

Radio Waves

Long wavelengths used in cell phones

Pavement might produce diffuse reflection, while a mirror produces ________ .

Plane, or regular, reflection

Put these from least energy to most energy - Radio, Ultraviolet, X - Rays, Visible, Microwaves

Radio Waves, Microwaves, Visible Light, Ultraviolet, X - Rays

Apparent colors that we see

Reflections of certain wavelengths of visible light

300,000,000 m/sec

The speed of all EM waves, the speed of light.

Prism

Used to seperate white light into its colors.

How are electromagnetic waves produced?

Vibrations of electrically charged particles.

Put thes three in order from slowest to fastest - Light, Sound, Water

Water, Sound, Light

Constructive interference

Waves combine to create a wave with greater amplitude.

Put these in order from shorteset to longest wavelengths - Radio, Ultraviolet, X - Rays, Visible, Microwaves.

X - Rays, Ultraviolet, Visible Light, Microwaves, Radio Waves

AM

amplitude modulation

FM

frequency modulation