physics

Question 1

what is a transverse wave?

Answer 1

they oscillate perpendicular
they don’t require a medium to travel
examples include em waves and light

Question 2

what is a longitudinal wave?

Answer 2

they oscillate parallel
they don’t require a medium to travel through
examples include sound seismic p-waves

Question 3

whats the equation for wave speed

Answer 3

frequency x wavelength

Question 4

what em wave has the lowest energy?

Answer 4

radio

Question 5

what em wave has a higher energy?

Answer 5

gamma rays

Question 6

what em wave has the lowest frequency?

Answer 6

radio

Question 7

what em wave has the highest frequency?

Answer 7

gamma

Question 8

what em wave has the smallest wavelength?

Answer 8

gamma

Question 9

what em wave has the largest frequency?

Answer 9

radio

Question 10

what is a use for radio waves?

Answer 10

tv signals

Question 11

what is a use of microwaves ?

Answer 11

reheating food and mobile phone connections

Question 12

what is a use for infrared?

Answer 12

heating and optical fibre communication

Question 13

what is a use for visible light?

Answer 13

seeing

Question 14

what is a use for uv light?

Answer 14

tanning and detecting forged bank notes

Question 15

what is a use for x-rays?

Answer 15

medical images

Question 16

what is a use for gamma rays ?

Answer 16

killing cancer cells

Question 17

what are the applications of em waves?

Answer 17

satellite communication, mobile phones, infrared, bluetooth and wifi

Question 18

what is satellite communication?

Answer 18

refers to any communication link that involves the use of an artificial satellite in its propagation path.

Question 19

what kind of signals does satellite communication use?

Answer 19

high power signals over long distances, concentrated by a dish antenna

Question 20

what kind of wave is used by satellite communication?

Answer 20

1-40 GHz microwaves

Question 21

how do mobile phones work with em waves?

Answer 21

A mobile phone receives microwave signals from a nearby phone mast (or ‘transmitter’) and sends microwave signals back.

Question 22

what kind of signal does a mobile phone use?

Answer 22

High power networked system, range of several km.

Question 23

what kind of wave is used by a mobile phone?

Answer 23

800 MHz to 2.6 GHz microwave borderline

Question 24

whats the difference between 2G 3G 4G 5G?

Answer 24

these offer increasing speeds for data. high frequencies have a greater data capacity but travel less distance 9in the air and penetrate into buildings less

Question 25

what is infrared?

Answer 25

this is a wireless mobile technology used for device communication over shorter ranges

Question 26

what kind of signal does infrared use?

Answer 26

Low power device to device links, range only a few meters

Question 27

what kind of em wave does infrared use?

Answer 27

IR wavelength 870 nm or 930-950 nm.

Question 28

what is one application of infrared

Answer 28

Used for remote controls and for data transfer between computers, phones etc. Requires lines of sight.

Question 29

what is bluetooth?

Answer 29

a wireless technology that allows the exchange of data between different devices

Question 30

what kind of signal does bluetooth use?

Answer 30

Low power device to device links, range up to about 10 m.

Question 31

what kind of em wave does bluetooth use?

Answer 31

2.4 to 2.4835 GHz borderline of microwave and radio waves

Question 32

what is wifi?

Answer 32

Wi-Fi is the wireless technology used to connect computers, tablets, smartphones and other devices to the internet.

Question 33

what kind of signal does wifi use?

Answer 33

Medium power networked system, range ~ 10-100m

Question 34

what kind of em waves does wifi use?

Answer 34

2.4 to 2.4835 GHz borderline of microwave and radio waves

Question 35

what is phase difference?

Answer 35

When two waves have the same frequency and wavelength, the phase difference tells us the difference in phase angle between the waves.

Question 36

what happens if two waves are in antiphase?

Answer 36

they will have a phase difference of 180 degrees meaning that the peaks will overlap with the throughs

Question 37

what is a coherent wave?

Answer 37

Coherent waves have a constant phase difference with one another. Waves can only be coherent if they have the same wavelength or frequency.

Question 38

when does destructive interference?

Answer 38

Destructive interference will take place when the peaks of one wave line up with the troughs of the other wave.

Question 39

when will constructive interference occur?

Answer 39

Constructive interference will take place when the peaks of one wave line up with the peaks of the other wave.

Question 40

constructive interference =

Answer 40

n λ

Question 41

destructive interference

Answer 41

ⁿ⁄₂ λ

Question 42

what is diffraction?

Answer 42

Diffraction changes the direction of a wave and causes it to spread. Diffraction occurs when a wave:
passes an edge
passes through a narrow gap
goes past an object

Question 43

whats changed during diffraction?

Answer 43

direction in which the wave is going

Question 44

when does maximum diffraction occur?

Answer 44

when the wavelength of the gap is equal to the gap

Question 45

a gap much larger than the wavelength causes …..

Answer 45

little spreading and a sharp shadow

Question 46

a gap similar to the wavelength causes ….

Answer 46

a lot of spreading with no sharp shadow