Waves and Optics

Wave Vocabulary

100

Distance between two consecutive points on a wave.

Wavelength

200

Measured in Hertz

Frequency

300

What is frequency?

The number of waves per second.

400

What is wave characteristic tells us the loudness of a sound wave?

Amplitude

500

What is the period of a wave?

Time per wave.  1/frequency

Types of wave

100

What is a longitudinal wave?

Particles move parallel to direction of motion.

200

What is a transverse wave?

Particles move perpendicular to direction of motion.

300

Describe a sound wave.

Longitudinal, needs medium, travels at 3.31 x 10² m/s. 

400

Describe a light wave.

Transverse, doesn't need a medium. Travels at 3 x 10⁸ m/s.

500

Describe an earthquake wave

Made up of longitudinal and transverse waves.

Surface

100

What is reflection?

When a wave bounces off a surface.  Incident angle = reflected angle.

200

What is refraction?

Bending of a wave when it enters a new medium.

Snell's Law

300

What is diffraction?

Bending of wave AROUND a surface or THROUGH an opening.  Bigger wavelength, smaller opening means more diffraction.

400

What is absorption?

Energy of the wave is absorbed into the new medium.

500

What is total internal reflection?

If a wave hits the new medium at an angle above the critical angle then it wont enter the medium.  It will all reflect.  Happens when index of refraction for new medium is much less than the index of refraction for the current medium.

Refraction

100

What happens to a light wave when it enters a medium with a greater n value?

Slows down, angle decreases, wavelength decreases. Frequency stays the same.

200

What happens to a sound wave when it enters a new medium?

Speeds up IF the n is greater (NOTE: Opposite to light)

300

What is the c = to in n = c/v?

c is the speed of light in a vaccuum = 3 x 10^8 m/s

400

What is the normal?

Perpendicular line with the surface.  Measure ALL angles with the normal.

500

If the speed of light in a new medium is 1.5 x 10⁸ m/s, what is the n value of that medium?

2

Optics

100

What describes the image in a plane mirror?

Upright, virtual, same size, same distance.

200

What describes the image in a convex mirror?

upright, virtual, smaller

300

Describe the 2 rays you draw to create an image in a mirror.

Parallel, then through F

Straight through C

400

Describe the 2 rays you draw to create the image in a lens.

Parallel, then through F.

Straight through the center of the lens.

500

What type of mirror would you use if you wanted to see all the details of your face?

Concave.