Show Me The Physics - Frequency of a Waves with answers Notes

Video Instruction

showmethephysics.com

Video

Show Me The Physics Website

This movie is part of the collection: Prelinger Archives

Production Company: ERPI Classroom Films, Inc. Distributed by Encyclopedia Britannica
Audio/Visual: sound, B&W
Creative Commons license: Public Domain

School blocks YouTube? Use link below.

SoundF_WL_Amplitude2.mp4

What is this speaker component called?

What kinds of waves does it produce?

High or low frequency?

Woofer, Outputs low frequency waves

II. Characteristics of Periodic Waves

A. Frequency(f) = #vibrations/sec

= # Cycles/# sec

= Hertz (Hz)

Source: Elroy M. Avery School Physics
(New York: Sheldon and Company, 1895) 202

Clipart ETC

hertz

Heinrich Hertz was the first to send
and receive radio waves.

Frequency

- Determined by
Source of Wave,

Not Medium

Cycle = (single vibration)

Ex)

How many cycles between the dots?

3 Cycles

Ex) 10 cycles pass a fixed point in a wave train in 5 seconds.
What is the frequency of the wave?

f =	10 cycles	=	2 cycles
	5 seconds		1 sec

f = 2 Hertz (Hz)

Top View of a Wave

[ HTML5 ]
showmethephysics.com

Sound Waves
David Kirby - U. of Calif.

Top view of a periodic wave
(Each line is a crest)

Crest
Physics 2000

Review - Longitudinal or Transverse?

[ Flash ]

Ex) A wave generator operating for
4 seconds produces the waves drawn below.

Top view of a periodic wave
(Each line is a crest)

How many waves are drawn between A and B? (Be careful!!)

What is the frequency of this
periodic wave train?

8 cycles

f = 8 cycles/4 sec

f = 2 cycles/sec

Ex) 2 cycles pass a fixed point in a wave train in 10 sec.

What is the frequency ?

f = # Cycles/# sec

f = 2 Cycles/10 sec

f = .2 Hz

• Sound, frequency is pitch.

Source: Elroy M. Avery School Physics
(New York: Sheldon and Company, 1895) 247

Clipart ETC

• Light, frequency is color.