Science physics revision

Question 1

What is a progressive wave

Answer 1

A wave that transfers energy from place to another without transferring material

Question 2

What is amplitude

Answer 2

maximum displacement from rest position

Question 3

What is wavelength

Answer 3

The distance between two matching points on neighbouring waves

Question 4

What is frequency

Answer 4

The number of waves that pass in a certain amount of time

Question 5

What is a transverse wave

Answer 5

The oscillations are perpendicular to the direction of wave travel

Question 6

What is a longitudinal wave

Answer 6

The oscillations are parallel to the direction of wave travel

Question 7

What is the equation to calculate wave speed

Answer 7

frequency times wavelength

Question 8

What is a stationary wave

Answer 8

A wave that travels in opposite directions and this requires the same frequency but different constant phase

Question 9

What is the phase difference of constructive difference

Answer 9

0

Question 10

What is the phase difference of destructive interference

Answer 10

180

Question 11

Describe bright spots

Answer 11

It has constructive interference, maximum amplitude and the peak meets with a peak and it has a phase difference of 0

Question 12

Describe dark spots

Answer 12

It has destructive interference, minimum amplitude, the peak meets with a through and the phase difference is 180

Question 13

What is refractive index

Answer 13

The ratio of the speed of light in a vacuum compared to the speed of light in a material

Question 14

What is the calculation to calculate refractive index

Answer 14

n=c over v

Question 15

What are the requirements for total internal reflection

Answer 15

The angle of incidence has to be greater than the critical angle and n1 has to be bigger than n2 ( more dense to less dense)

Question 16

What is excitation

Answer 16

When the electrons absorb the wave as light and they jump up levels

Question 17

What is dexecitation

Answer 17

The electrons fall back down to their ground energy level and they release energy as light

Question 18

What is the distance of the first harmonic

Answer 18

4m

Question 19

What is the distance of the second harmonic

Answer 19

2m

Question 20

What is the distance of the third harmonic

Answer 20

1.5m

Question 21

Describe bluetooth

Answer 21

lower power device to device links range up to 10m, the frequency is about 2.4 to 2.485

Question 22

What are the advantages of microwaves

Answer 22

they can pass through the ionosphere
has better satellite communication
has a higher bandwitdth

Question 23

What are the disadvantages of microwaves

Answer 23

transmission is affected by fog and rain
cannot communicate with vessels underwater
can be only be used in a line of sight

Question 24

what are the advantages of radiowaves

Answer 24

can reach receivers out of site of the transmitter
can reflect off the ionosphere

Question 25

what are the disadvantages of radiowaves

Answer 25

low bandwitdth cannot carry as much information it is also subject to interference

Question 26

what are the advantages of digital signals

Answer 26

signals can be regenerated so is there is no loss of information signals can carry more information because the signal is more multiplexed there is less energy wasted because of total internal reflection

Question 27

what are the disadvantages of digital signals

Answer 27

they are easily damaged because they are so fragile and brittle poor joints lead to poor signal strength so the signal is poor information can be scrambled because of sampling errors

Question 28

what are the advantages of the analogue signal

Answer 28

it is best fitted for audio and video transmission it posesses higher density its easier in processing

Question 29

what are the disadvantages of the analogue signal

Answer 29

data can be corrupted in analogue signals it is quite difficult to synchronize an analogue sound it also posess lower quality than digital

Question 30

what are the advantages of infrared

Answer 30

does not interfere with other devices as the frequency is higher than bluetooth has better quality and communication between devices due to higher frequency

Question 31

what are the disadvantages of infrared

Answer 31

needs a line of sight works with one device at a time sunlight will interfere with the signal

Question 32

what are the advantages of bluetooth

Answer 32

does not need to be in direct line of sight bluetooth can be used on more than one device at the same time

Question 33

what are the disadvantages of bluetooth

Answer 33

low bandwidth interference with other bluetooth devices on similar radio frequencies if close by

Question 34

How do fibre optics work?

Answer 34

transfer information using pulses of light. Each pulse undergoes total internal reflection down the fibre optic cable. The core must be as transparent as possible to prevent any attenuation. Cladding is used to protect the core to prevent cross over between cables. This allows for total internal reflection to take place. It must have a lower refractive index index than the the core.

Question 35

True or false, waves in a string use longitudinal waves?

Answer 35

False, they use transverse waves