waves and wave properties

Question 1

What is a wave?

Answer 1

A wave transfers energy from one place to another as a result of something vibrating / oscillating

Question 2

What are longitudinal waves?
Give an example

Answer 2

In longitudinal waves the wave travels / energy is transferred parallel to the oscillations (eg: sound)

Question 3

What are transverse waves?
Give an example

Answer 3

In transverse waves the wave travels / energy is transferred perpendicular to the oscillations (eg: light)

Question 4

Which travels faster - light or sound?

Answer 4

light travels faster than sound

Question 5

definition of Compression

Answer 5

Compression (longitudinal wave) - where the particles are compressed and bunched together

Question 6

defenition of wavelength

Answer 6

Wavelength- the length of one full wave between two adjacent identical points

Question 7

amplitude

Answer 7

Amplitude- the maximum displacement of a wave or particle from its equilibrium position

Question 8

rarefaction

Answer 8

Rarefaction (longitudinal wave) - where the particles are spaced further apart

Question 9

frequency

Answer 9

frequency- the number of oscillations per second

Question 10

time period

Answer 10

time period- the time for one full oscillation

Question 11

What properties of a sound wave affect the pitch and volume?

Answer 11

Pitch is affected by frequency - the higher the frequency, the higher the pitch

Question 12

What property of a sound wave affects the volume?

Answer 12

Volume is affected by amplitude - the larger the amplitude, the louder the volume

Question 13

Does sound travel fastest in solids, liquids or gases? Why?

Answer 13

Sound travels fastest in solids as the particles are closest together, so collisions between particles occur more frequently

Question 14

What is echolocation?

Answer 14

Echolocation is the principle of using echoes to determine the distance to an object

Question 15

how can echoes be used to determine the speed of sound and/or the distance to an object?

Answer 15

The time taken for a sound wave to travel and return is divided by two
*This is because it’s the time to go there and back
If the distance to the object is known, then the speed of sound in the medium can be calculated (or vice versa)

speed over distance

Question 16

What is the unit for sound?

Answer 16

decibels

Question 17

What is the equation for working out wave speed?

Answer 17

Speed = Wavelength x Frequency

Question 18

What is the Law of Reflection?

Answer 18

Angle of incidence = angle of reflection

Question 19

What is the normal line?

Answer 19

The normal is an imaginary line perpendicular to a surface

Question 20

Where are the angles of incidence and reflection measured from?

Answer 20

The angles of incidence and reflection are measured between the relevant light ray and the normal

Question 21

What is the nature of the reflected image like in a plane mirror?

Answer 21

The reflected image in a plane mirror is or appears:
• The same size as the object
• The same distance into the mirror as the object is from the mirror

Question 22

What objects reflect light?

Answer 22

All objects we can see reflect light - we see them because they reflect light into our eyes

Question 23

What happens to waves when they enter a medium of different density?

Answer 23

Waves change speed when they enter a medium of different density

Question 24

What is refraction?

Answer 24

Refraction is the change in direction of a wave when it enters a different medium at an angle

Question 25

Which way will light refract when it enters a medium of different density at an angle?

Answer 25

Light refracts towards the normal if it enters a more dense medium Light refracts away from the normal if it enters a less dense medium

Question 26

What is "white" light?

Answer 26

White light is what we see when all the colours of the visible spectrum (the same colours as we see in a rainbow) are combined

Question 27

What causes an object to look white?

Answer 27

A white object will reflect all colours of light

Question 28

What causes an object to look black?

Answer 28

A black object will reflect no colours of light

Question 29

What are the primary colours of light?

Answer 29

Red, blue and green

Question 30

What are the secondary colours of light and which primary colours make them?

Answer 30

Yellow - red and green Cyan - green and blue Magenta - red and blue

Question 31

Why do we see objects colours?

Answer 31

An object will look the colour that it does because of the colour(s) of light it reflects

Question 32

What happens to colours that are not reflected?

Answer 32

Colours that are not reflected are absorbed

Question 33

what colour does a red object in red light look like?

Answer 33

red

Question 34

a red object in blue light will look….

Answer 34

black

Question 35

a yellow object in red light will look…

Answer 35

red

Question 36

a red object in blue light will look….

Answer 36

black

Question 37

A yellow object in red light will look…

Answer 37

red