revision sound. doppler effect doppler effect as the change in frequency (or pitch) of the sound...
TRANSCRIPT
REVISIONSOUND
DOPPLER EFFECT• Doppler effect as the change in frequency (or
pitch) of the sound detected by a listener because the sound source and the listener
have different velocities relative to the medium of sound propagation
𝑓 𝐿=𝑣±𝑣 𝐿
𝑣±𝑣𝑆
𝑓 𝑆
FORMULA
𝑓 𝐿=𝑣±𝑣 𝐿
𝑣±𝑣𝑆
𝑓 𝑆Frequenc
y of listener
Frequency of
sourceSpeed of source
Speed of listener
Speed of sound in medium
Speed of sound in medium
f
APAR
T
𝑓 𝐿=𝑣±𝑣 𝐿
𝑣±𝑣𝑆
𝑓 𝑆+-
f
TOW
ARD EACH
OTH
ER
𝑓 𝐿=𝑣±𝑣 𝐿
𝑣±𝑣𝑆
𝑓 𝑆+-
ELECTROMAGNETIC SPECTRUM
light wavesIt does NOT need a medium to propagate
It consists of seven main groups
DOPPLER EFFECT with LIGHT
DOPPLER EFFECT with LIGHT
DOPPLER EFFECT with LIGHT
DOPPLER EFFECT with LIGHT
-1
Dolphins use ultrasonic waves to explore their surroundings.
When a dolphin is 100m from a rock, it emits an ultrasonic wave
with a frequency of 250 kHz,
while swimming at 20m.s towards the rock.
Assu
-1
.
a Calculate the frequency of the sound waves that reach the rock
b When the dolphin is 50m from the rock, i
me that the speed of sound
t emits another wave
of 25
in water is
0 kHz .
How do
1500m.
es
s .
this preceived frequency relate to the answer is a)
GENERAL DOPPLER EFFECT
The siren of a stationary ambulance emits ound
with a frequency of 700 Hz.
The driver of a car approaches the ambulance and
then passes it by. He perceives that the frequency
of the siren changes by
s
-1
a Name and state the wave phenomena
b Take the speed of sound in air as 340m.s and
calculate the speed of the car when it passes
the ambul
80Hz
ance
CHANGES IN FREQUENCY
a)
b)