Waves. Unit 4: Pages 334 to 421 Chapter 8 in text. What do you already know?. What is a wave? Where do we “see” waves in our everyday lives? Why are waves important to physicists?. Waves - Everyday. Earthquakes Tsunamis Sound waves Radio waves Light waves*** Regular ocean waves
Unit 4: Pages 334 to 421
Chapter 8 in text
TRUE or FALSE:
Transverse waves are when the displacement is perpendicular to the direction of the wave…
Transverse waves are the ones most people can draw.
Example. Water ripples on the surface of the pond, S waves (earthquakes), radiowaves, x-rays, and light waves (all electromagnetic waves) x-rays
Longitudinal waves are when the displacement is parallel to the direction of the wave…
Example: Sound waves, ultrasound waves
c. north to south only
d. both northward and southward
Wavelength - the shortest distance between two repeated points in a wave. Think of a wavelength as the distance between two humps.
Symbol = λ (lamda)
Unit = metre (m)
Frequency - the number of complete waves produced per second.
Symbol = f
Units = Hertz (Hz) 1 Hz = 1/s
(Named after Henry Hertz who discovered radio waves)
Formula: where N is number of cycles, t is time
Formula where T is the period
Period - time taken to produce one complete wave.
Symbol = T
Units = seconds (s)
Formula: where t is time
NOTE: DO NOT GET CONFUSED WITH WAVELENGTH AND PERIOD – MATH 11 IS NOT PHYSICS 11!
from its undisturbed position. Think of the amplitude as the height of a hump.
Consider the diagram below in order to answer questions #1-2.
GIVEN: f = 440 Hz
T = 1 / f = 1 / (440 HZ) = 0.00227 s
fThe Wave Equation
The wave equation relates the speed of the wave to its frequency and wavelength:
Wave speed (v) = frequency (f) x wavelength ()
in m/s in Hz in m
= 1.008 m/s
f = 2.50/1.8
f = 1.4 Hz
Page 343, questions 1, 2, 3, 4, 6, 7