Download Quiz Cards P1 Topic 4

1)
a)
b)
c)
Ultrasound is ……..
Longitudinal waves below 20 Hz
Longitudinal waves above 20,000 Hz
Transverse waves above 20,000 Hz
Answer.
a) Longitudinal waves above
20,000 Hz
P1 TOPIC 4
M. Rahman
2) Human hearing range is;
a) Above 20,000 Hz
b) Below 20 Hz
c)
Between 20-20,000 Hz
Answer
c) Between 20-20,000 Hz
P1 TOPIC 4
M. Rahman
3) How is ultrasound used for in
foetal scanning?
Answer
• Ultrasound waves pass through the
body;
• at boundaries between two different
media;
• some waves are reflected back
• and detected to produce a computer
image
P1 TOPIC 4
M. Rahman
4)How is Sonar used in boats and
submarines to detect stuff in water?
Answer
• Boats and submarines emit ultrasound,
• which is reflected off the object (ie
boats, sea bed, marine animals)
• The time-delay between emitting and
detecting the waves is used to calculate
how far the other object is using
• S=d/t
P1 TOPIC 4
M. Rahman
5) Calculation: A pulse of ultrasound takes 5
seconds to travel from a boat to a ship wreck
under the sea and back again. How far away is
the shipwreck? (speed of sound in water = 1520
m/s)
Answer
• Speed = distance/time
• rearrange, distance = speed x time
= 1520 x 5
= 7200 m
• Its 5s there and back so the ship wreck is only
half the distance away so divide by 2.
•
= 7200/2
= 3600 m
•
P1 TOPIC 4
M. Rahman
6) Infrasound is ……..
a)
Longitudinal waves below 20 Hz
b)
Longitudinal waves above 20 Hz
c)
Transverse waves above 20,000 Hz
Answer
a) Longitudinal waves below 20 Hz
P1 TOPIC 4
M. Rahman
7) Explain how animals use
infrasound?
Answer.
• Elephants use infrasound to
communicate with other members
of their heard over long distances.
• Tigers use infrasound in the growls
and roars which can be heard by
rivals or mates
P1 TOPIC 4
M. Rahman
8) Why can some volcanic eruptions be
detected at a distance?
Answer
• Infrasound is long wavelength,
• that means they can travel long
distances and diffract around
objects.
P1 TOPIC 4
M. Rahman
9)
1.
2.
3.
Which of these statements are false?
Low frequency, long wavelength sounds travel further.
Larger animals (elephant) make higher frequency sounds
compared to little ones (mice).
Volcanic eruptions make high frequency sounds that can be
heard from a long distance.
Answer
False statements are:
2. Larger animals (elephant) make higher
frequency sounds compared to little ones (mice).
3. Volcanic eruptions make high frequency
sounds that can be heard from a long distance
P1 TOPIC 4
M. Rahman
10) Which of the following statements are false?
1. Sounds travel further in air then in water.
2. Whales can communicate over larger distances than elephants can.
3. Animals that can use infrasound can communicate further
distances than animals that use higher frequencies.
Answer.
False statements are:
1. Sounds travel further in air then in
water.
P1 TOPIC 4
M. Rahman
11) The structure of the earth from inside out are:
a) Crust, mantle, outer core; inner core
b)
outer core; mantle; inner core; crust
c)
Inner core; outer core; mantle; crust
Answer.
c) Inner core; outer core; mantle;
crust
P1 TOPIC 4
M. Rahman
12) What is the inner core and outer
made from?
Answer.
Inner core –solid
Outer core -liquid
P1 TOPIC 4
M. Rahman
13) What is the mantle made from?
Answer
• Molten rock
• Heat is produced, causing
convection currents.
P1 TOPIC 4
M. Rahman
14) Explain how heat from the mantle
causes earth quakes? (3)
Answer
a)
Heat from the mantle produce convection currents;
b)
causing the plates to move
c)
At plate boundaries, plates may rub against each
other,
d)
causing pressure to build up.
e)
Sudden release of pressure as a result of the
plates sliding past each other causes an earth
quake.
P1 TOPIC 4
M. Rahman
15) Why is it difficult to predict an
earth quake? (3)
Answer
• Earthquakes are totally random –
• although there are areas where they are
more likely to happen than others (near
fault lines).
• The fault line has a build up of stresses
and any part of that fault line could snap
out of line at any moment.
P1 TOPIC 4
M. Rahman
16). Give two ways seismic waves are
created
Answer.
• Earthquakes
• Explosions
P1 TOPIC 4
M. Rahman
17). What instrument is used to detect
seismic waves created from an earth
quake?
Answer
• Seismometer.
P1 TOPIC 4
M. Rahman
18) What are the two types of seismic
waves?
Answer.
P waves
S waves
P1 TOPIC 4
M. Rahman
19) What are the properties of P-waves?
(4)
Answer.
• These are Push-Pull waves
• They are longitudinal
• They can travel through liquid and solid so
they can travel through the earth’s core.
• They travel fast.
• They are bent by the changing density of
the rock.
• They are bent sharply when the material
changes suddenly.
P1 TOPIC 4
M. Rahman
20) What are the properties of S-waves ?(4)
Answer.
• They are Side to Side waves.
• They are transverse
• They can only travel through solids.
• They are slower than P-waves.
• They are bent by the changing density
of the rock.
• They are bent sharply when the
material changes suddenly
P1 TOPIC 4
M. Rahman
21) What happens when seismic waves reach a
boundary between different layers of the earth?
Answer.
• They are reflected and
• refracted
P1 TOPIC 4
M. Rahman
22) What is the phenomenon called which causes
the waves to change speed and direction?
a) Reflection
b) Refraction
c)
Diffraction
Answer.
b) Refraction
P1 TOPIC 4
M. Rahman
23) Why does the speed and direction
(refraction) of the seismic wave
change?
Answer
When there is a change in
density-between different layers
of material.ie between mantle and
the outer core?
P1 TOPIC 4
M. Rahman
24) When there is a gradual change in speed
a curved path is made by the wave, what
happens when there is a sudden change in
properties/densities between layers?
Answer
• The wave speed changes
abruptly and
• and the path has a kink
P1 TOPIC 4
M. Rahman
25) Which waves are detected first by a seismometer
travelling from the epicentre of an earth quake.
A) P-waves
B)
S-waves
Answer
A) P-waves-they travel the
fastest.
P1 TOPIC 4
M. Rahman
26) What does arrival time mean?
Answer
The time taken for a wave (P-wave
or S-wave) to travel from the
epicentre of the earth quake to
the seismometer?
P1 TOPIC 4
M. Rahman
Describe how scientists use P waves and S
waves to locate the position of an
underground earthquake (6).
• Seismic waves are detected by seisometers
• You need at least 3 seisometers
• The arrival time of s waves will be slower then p
waves.
• The further the seisometer is away from earth
quake the greater the difference between the
arrival times.
• Distance can be worked out because the arrival
time is known
• A circle is drawn to indicate the distance
• The point at which three circles meet is called the
epicentre
P1 TOPIC 4
M. Rahman