Chapter 11 Wave Properties

Question 1

What is a wave and what can it be used for

Answer 1

A wave is a means of transfering energy from one place to another without a transfer of matter between the two points

You can also use waves to transfer information mobile phone,radio

Question 2

What’s a mechanical wave and examples

Answer 2

vibrations that travel through a medium (a substance):
Sound waves, water suface waves

Question 3

What’s an electromagnetic wave and examples

Answer 3

all travel through a vacuum at the speed of 300,000 km/s. No medium is needed
Light waves, radio waves and microwaves

Question 4

Whats a transverse wave

Answer 4

The direction of oscillation of a wave is perpendicular ( 90° ) to the direction of motion of the wave. All EM waves are transverse waves.

Question 5

What’s longitdunal waves

Answer 5

The direction of oscillation of a wave is parallel to the direction of motion of the wave.

Question 6

What type of waves are mechanical waves

Answer 6

They can be transverse or longitdunal

Question 7

What is the amplitude of a wave

Answer 7

Amplitude - the maximum displacement of a point of a wave from its rest position

Question 8

What is the frequency of a wave

Answer 8

Frequency - the number of waves passing a point each second

Question 9

What is the period of a wave

Answer 9

Period - the time taken for a full cycle of the wave, usually measured from peak to peak, or trough to trough

Question 10

What is the wavelength of a wave

Answer 10

Wavelength - distance covered by a full cycle of the wave, usually measured from peak to peak, or trough to trough

Question 11

Period equation

Answer 11

T = 1/f
Period = 1 / frequency (Hz)

Question 12

Frequency equation

Answer 12

F = 1/T
Frequency(Hz) = 1 / T

Question 13

The wave equation

Answer 13

V = f x wavelength
Velocity (ms^-1) = freuency (Hz) x wavelength(m)

Question 14

What is displacement -(meausred in metres) in a wave

Answer 14

The change in posistion of an object

Question 15

How to measure speed of sound in air(calculation)

Answer 15

Speed = distance / time taken

Question 16

How to measure wave properties experiment 1 (ripple tank and water waves) - step by step

Answer 16

1.-Set up the apparatus as shown and fill the ripple tank with water to a depth of no more than 1 cm

2.-Turn on the power supply and the light source to produce a wave pattern on the screen

3-The wavelength of the waves can be determined by using a ruler to measure the length of the
screen and dividing this distance by the number of wavefronts

4.-The frequency can be determined by timing how long it takes for a given number of waves to pass a particular point and dividing the number of wavefronts by the time taken

5.-Record the frequency and wavelength in a table and repeat the measurements

Question 17

How to measure wave properies experiment 2 (strings and masses)

Answer 17

1-Set up the apparatus as shown, then adjust the frequency of the signal generator until a “solid” wave is produced

2.-Once the “solid” wave is produced, record the frequency shown on the signal generator

3.-Use a ruler to measure the wavelength, the length to measure will depend on the number of “solid” waves produced. Or measure the length of multiple wavelengths, and divide by the number of wavelengths seen

4.-Repeat the procedure by adjusting the frequency until another “solid” wave is produced

Question 18

Ray diagram
What is the bottom bar?
Line going through middle?
Left angle?
Left ray?
Right angle?
Right ray?

Answer 18

1-boundary
2-the normal
3-angle of incident
4-ray of light or incident ray
5-angle of reflection
6-reflected ray

Question 19

Why does light change direction ( truck example)

Answer 19

A truck changes direction as it slows down
Light is refracted when it slows down
Waves are refracted when they slow down

Question 20

What is refraction

Answer 20

when a wave changes direction as it changes speed when it passes from one medium to another. So the wavelength change as well but the frequency remain unchanged.

Question 21

What happens after waves go through deep water to shallow water

Answer 21

Speed is less in shallow water. So edge of wave front entering shallow water slows down but the part of the wave front in deeper water continues at a higher speed leading to a change direction of the wave fronts

Question 22

What else happens to objects when it’s hit by light (not reflected or refracted)

Answer 22

Absorbed or transmitted