Combined Waves Topic Vocabulary Flashcards Preview

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Flashcards in Combined Waves Topic Vocabulary Deck (31):
1

Angle of reflection

the angle between the reflected ray and the normal

2

Angle of incidence

the angle between the normal and the incident ray

3

Angle of refraction

the angle between the refracted ray and the normal

4

Snell's Law

when an incident ray passes into a material: n = sin i ÷ sin r

5

Law of reflection

in reflection at a surface, the angle of incidence is equal to the angle of reflection

6

Diffraction of waves

when waves meet a gap in a barrier, they carry on through the gap, but the waves spread out to some extent into the area beyond the gap

7

Dispersion of white light

when white light passes through a prism, it splits into different spectral colours and wave lengths (dispersion) and the different colours of the spectrum seperate

8

Refraction

light waves change speed when they pass across the boundary between two differenct media

this causes them to change direction

9

Reflection

there is reflection when waves bounce off a surface

10

Real image

produced when real rays of light cross and can be projected

11

Virtual image

produced when virtual rays of light cross

can't be projected

it is the same size, laterally inverted and the same distance beyond the mirror as the real image 

12

Transverse Wave

produced when the vibrations are perpendicular to the direction of energy

e.g. light waves

13

Longitudinal wave

produced when the vibrations are parallel to the direction of energy

e.g. sound waves

14

Refractive index

refractive index (n) = speed of light in air (3x108) ÷ speed of light in material

15

The electromagnetic spectrum

a continuous range of wavelengths

16

Frequency

the number of vibrations (or waves) per second in Hertz (Hz)

17

Wavelength

the shortest distance between two parts of a wave that are in phase (doing the same thing)

18

Amplitude

the distance from the centre of a wave to the peak or trough

19

Speed of light

the distance light can travel in a unit of time through a given substance

20

Speed of light in air

3x10m/s

21

Speed of sound in air

343 m/s

22

Echo

a sound caused by the reflection of sound waves from a surface back to the listener

23

Ultrasound

sound with a frequency greater than 20,000Hz (20 kHz)

this is above the range of human hearing

24

Reliability

a set of results that are repeated and the spread of the readings is small (or they cluster together)

25

Validity

an experiment is valid if you measured what you set out to investigate

26

Fair test

a test in which only the independent variable has been allowed to affect the dependent variable e.g. by keeping all other variables constant

27

Parallax error

caused by not having the eye in line with the object being measured and the scale being measured against

28

Human error

humans making small mistakes when taking readings

this can be minimised by good experimental technique and repeating readings

29

Random error

produced either side of the true value

caused by human error or unknown and unpredictable changes in the experiment (e.g. measuring instruments or in the environmental conditions)

30

Precision

the result of using the correct piece of equipment with appropriate resolution or smallest division

precise measurement are ones in which there is very little spread about the mean value

31

Accuracy

reliable and precise measurements can produce results very close to the true value and therefore be accurate