National 4-5
Classwork
1 Speed of light
1.
2.
3.
4.
5.
2.
Calculate the distance that light travels in
a) 10 s
b) 5 minutes
A boy hears thunder 4 s after he sees lightning.
a) If the speed of sound is 340 ms-1, how far is the boy
from the lightning strike?
b) How long does the light take to travel this distance?
25 cm
12 m
a)
b)
3.
A
C
Radio waves travel at the same speed as light. A radio signal
is transmitted from Edinburgh 50 000 km up to a satellite.
The satellite retransmits the signal 50 000 km to a receiving
station in New York. How long does it take for the signal to
travel from Edinburgh to New York?
Twins, Steven and Stuart both want to hear a concert which
is at Wembley. Steven is at Wembley, 250 m from the
speakers. Stuart is in Peru 15 000 km away and listens to the
concert on the radio.
a) How long does it take the sound to reach Steven?
b) How long does it take the radio signal to reach Stuart?
c) Which of them hears the start of the concert first?
20 waves pass a point in 4 s.
a) What is the frequency of the waves?
b) What is the period of the waves?
What is the amplitude of the wave shown?
What is the wavelength of the wave?
All the waves shown below are produced in 2 s.
Microwaves travel at the same speed as light. How long does
it take a microwave signal to travel 450 km between
Inverness and Stranraer?
2 Wave Properties
1.
Unit 2a – Waves, Light and EM Spectrum
D
160 cm
B
160 cm
a)
b)
c)
d)
e)
f)
Calculate the frequency of the waves.
Calculate the wavelength of the waves.
Calculate the period of the waves.
Calculate the amplitude of the waves.
Name points A and B
Calculate the distance between points C and D
4.
A generator producing waves vibrates 480 times in 1 minute.
a) What is the frequency of the waves?
b) What is the period of the waves?
5.
A boat is anchored in a bay. 10 waves pass it in 1 minute. The
distance between the crests of the waves is 15 m
a) What is the frequency of the waves?
b) What is the wavelength of the waves?
c) What is the speed of the waves?
National 4-5
Classwork
3 Wave equation
Unit 2a – Waves, Light and EM Spectrum
4 More difficult wave questions
1.
A wave has a wavelength of 34 cm and a frequency of 75 Hz.
Calculate its speed.
2.
A wave traveling at 25 ms-1 has a wavelength of 7.5 mm.
Calculate its frequency.
1.
A wave has a wavelength of 12 µm and a frequency of 6 GHz
a) Calculate the wave speed.
b) How far does the wave travel in 1 minute?
2.
A wave travels 360 km in 4 minutes. It has a period of 75 µ s.
a) Calculate the wave speed.
b) Calculate the frequency of the wave.
c) Calculate the wavelength.
3.
1500 waves pass a point in 1 minute with a wavelength of 6 mm.
a) Calculate the wave speed.
b) Calculate how far the wave travels in 3.25 minutes.
4.
A pulse of light has a wavelength of 700 n m. It travels
through diamond for 8.2 ps at a speed of 125 Mm s-1.
a) Calculate the distance traveled by the light in the
diamond.
b) Calculate the frequency of the light in the diamond.
c) Calculate the distance that the light would have traveled
in air in the same time.
-1
3.
A wave has a velocity of 18 ms and a frequency of 9 Hz.
a) Calculate the wavelength of the wave.
b) Calculate the period of the wave.
4.
A light wave has a wavelength of 5x10-7 m. Calculate its
frequency.
5.
What is the wavelength of a microwave which has a frequency
of 12,500 MHz?
6.
Radio 1 has a wavelength of 285 m. What is its frequency?
7.
96 waves arrive at a beach every minute. The speed of the
waves is 4.8 ms-1.
a) Calculate the frequency of the waves.
b) Calculate the wavelength of the waves.
8.
A source provides 400 waves every minute. If the speed of
the waves is 8 mms-1, find the distance between adjacent
crests.
National 4-5
Classwork
Unit 2a – Waves, Light and EM Spectrum
6 Light
Copy and complete the following diagrams.
a)
b)
air
glass
glass
air
incident
incident
ray
ray
1.
2.
6.
A man can read his book with no trouble but needs glasses to
see his cat at the bottom of the garden.
a) What eye defect is he suffering from?
b) What sort of lenses will be in his glasses?
7.
A woman can watch a football match with no difficulty, but
needs her glasses to read the match report in the paper the
next day.
a) What eye defect is she suffering from?
b) What sort of lenses will be in her eyes?
8.
Copy and complete the diagrams below to show the optical
component which must be in the box and its correct position.
Copy and complete the following diagrams.
a)
b)
3.
Describe the shape of the lens in the eye when looking at :
a) distant objects.
b) objects which are close by.
4.
Draw diagrams to show where parallel rays of light are
focused:
a) for someone suffering from long sight.
b) for someone suffering from short sight
5.
Describe the vision of a man suffering from:
a) short sight
b) long sight.
a)
b)
c)
d)
National 4-5
Classwork
5 Sound, the wave equation and speed, distance and time
1.
The range of human hearing is approximately 20 Hz - 20 kHz.
If the speed of sound in air is 340 ms-1, calculate:
a) the minimum wavelength that is heard.
b) the maximum wavelength that is heard.
2.
A bat can hear sound with a wavelength of 8.5 mm. Show by
calculation if a bat can hear ultrasound.
3.
A series of sonar pulses is used by fishermen to detect shoals
of fish under the water. The speed of sound in water is 1200
ms-1.
a)
b)
c)
d)
4.
An echo is received after 0.3 s. How far has the sound
traveled?
Another echo is received after 120 ms. How far has the
sound traveled?
How deep is the water?
How deep is the shoal of fish?
An ultrasound signal, with a period of 0.75 µs and a
wavelength of 1.125 mm, is used to examine an unborn child.
a) Calculate the frequency of the ultrasound used.
b) Calculate the speed of the ultrasound.
c) how long will it take for an echo to be received from a
depth of 6 cm?
Unit 2a – Waves, Light and EM Spectrum
7 The electromagnetic spectrum
1.
One use of X-rays in medicine is to find broken bones.
Explain how this is done.
2.
What can be used to detect X-rays?
3.
Describe what is meant by computerized tomography
4.
What is another name for infra red radiation
5.
Give one example of how infra red radiation is used for
treatment in medicine.
6.
Give one example of how infra red radiation is used for
diagnosis in medicine.
7.
Give two examples of how ultra violet radiation is used in
medicine.
8.
Give one danger of too much exposure to ultra violet
radiation.
9.
Place these three radiations in order of increasing
wavelength:
infra red;
ultra violet;
visible light.