Waves

Question 1

mechanical waves

Answer 1

require some medium through which to travel

transverse and longitudinal waves

Question 2

transverse wave

Answer 2

the medium is displaced perpendicularly to the direction of wave propagation
ex: waves on string

Question 3

longitudinal wave

Answer 3

sound wave, one in which the medium is displaced parallel to the direction of wave propagation
ex: sound wave in air

Question 4

wavelength * frequency =

Answer 4

velocity

Question 5

velocity of wave is dictated by….

Answer 5

the medium through which it travels

Question 6

for a gas, the velocity of a wave increases with…

Answer 6

temperature

Question 7

intensity

Answer 7

power in waves, W/m^2

intensity increases with the square of the amplitude and the square of the frequency for all waves

Question 8

intensity level

Answer 8

logarithmic scale of intensities, in decibels
= 10log(I/I_0)
I_0 = threshold intensity of human hearing

Question 9

if intensity increases by a factor or 10, the decibels increase by the addition of …

Answer 9

10 decibels

Question 10

beats

Answer 10

when two wave with slightly different frequencies are superimposed
beat frequency = absolute value(f1-f2)

Question 11

pitch

Answer 11

how high or low a note sounds

correlates with frequency, high note has nigh pitch and high frequency

Question 12

when a wave reflects off a denser medium…

Answer 12

the wave is inverted, 180 phase shift

Question 13

node vs. antinode

Answer 13

node = never displaced
antinode = experience max constructive interference

Question 14

harmonic series

Answer 14

list of wavelengths from largest to smallest of possible standing waves for a given situation

Question 15

first harmonic / fundamental wavelength

Answer 15

longest wavelength of possible standing wave, fewest number of nodes
distance from one wall to the other is 1/2 a wavelength

Question 16

resonate

Answer 16

vibrate at its natural frequency/resonant frequency

resonance = when natural frequency and driving frequency are equal

Question 17

simple harmonic motion is a ____ function in time

Answer 17

sinusoidal

Question 18

the acceleration of any system in simple harmonic motion is proportional to….

Answer 18

the displacement of that system, but opposite in sign

acceleration and displacement are related by square of frequency

Question 19

for mass-spring system and for pendulum, period is ____ of displacement

Answer 19

period is independent of displacement

Question 20

Doppler Effect

Answer 20

waves are unaffected by the speed of the source which produces them
f_o - f_s/f_s = v/c
wavelength_0 - wavelength_s_/w.l._s = v/c

Question 21

equation for harmonic series where each end is tied down as node or where each end is loose creating an antinode

Answer 21

L = n*wavelength_n/2
n= 1,2,3...= number of harmonic
L = distance between 2 ends of string

Question 22

equation for harmonic series for one end tied/open

Answer 22

L = n*wavelength_n/4
n = 1,3,5