waves

Question 1

which light has a greater absalute refactive index when passing through meterials, red or blue.

this is because… (use the equation)

because the red light lowers the refractive index of n1 and n2 the same amount the the reletive refrective index will be _____ the blue light.

Answer 1

red has lower absalute refractive index when passing through meterials compread to blue light

absalute refractive index (n) = c/c(s)
red light has a longer wavlenth thereofre tavels faster thourgh meterials
therefore
has a lower absalute refrective index for the same meterial when compeared to blue light.

lower

Question 2

what does d represent in the diffraction
grating equation dsinθ=nλ

Answer 2

d is the distence between each slit

therefore
1/d would be the nomber of slits per m

Question 3

what is the same and what is diffrent between single slit and dubble slit diffreaction pattern

(not fineshed flash card)

Answer 3

same:
both have the same width of outer maxima

diffrent:
single slit has a wider central maxima

Question 4

absalut refractive index is always ______ then 1

give absalute refractive index formula

Answer 4

greater

n=c/c(s)

absalute refractive index = speed of light in a vaccume / speed of light in the meterial

Question 5

what needs to be true for yongs dubble slit experiment with equation W=λD/S to work

why?

Answer 5

D needs to be much much greater then S (D needs to be large)

because small angle approximation is used to assume that the rays are parellel

Question 6

explain how a stationary wave is formed (4mark)

Answer 6

• the wave reflects of a closed end
• outgoing wave interfers with the reflected wave
• the waves meet in phase and creat points of maximum amplitude (antinodes)
• the waves meet out of phase to create points of 0 amplitude (nodes)

Question 7

what is the value of θ for the max order that can be seen for a diffrection grating

Answer 7

max order for a diffraction grating is when θ = 90
therefore
when sinθ = 1

Question 8

when light enters a opticaly denser meterial (meterial with high refractive index) what happens to
- speed of the ray of light
- frequency of the ray of light
- wavelength of the ray of light

Does this light bend to words the normal or away

Answer 8

• speed decreses
• frequency stays the same
• wavelenth decreses

Towards

Question 9

how do you increase the natual frequency of a mass spring system

Answer 9

decrease the mass
or
increase the spring constent (stiffness)

Question 10

with open tubes where is the node and anti node

Answer 10

node at the closed end

anti node is at the open

Question 11

in 2 source with 2 load speakers:
explain why the sound goes form load to quite as it goes from A to B

Answer 11

• the sound waves form the 2 speakers superpose
• at A and B the 2 waves have 0 path diffrence, are in phase, maximum amplitude is produced
• at it moves from away form A the path diffrence decreases , decreseing phase diffrence, decresing loadness/amplitude
• moving towards B the path diffrence decreases, decresing phase diffence, increseing amplitude/loadness

Question 12

for 2 waves to cancle out what need to be true

Answer 12

both waves are in phase and have the same amplitude

Question 13

exam question:
describe the structure of a step index optical fibre outlining the purpose of the core and the cladding (3 mark)

Answer 13

• the core is opticaly denser then the cladding around it, this allowes total internal reflection to occure
• the cladding offers a layer of protection, preventing the core from obtaining stratches that could lead to light excaping the core
• the core is a transmission meduim for em waves to progress

Question 14

same em spectrum from larger λ to smaler λ (7)

Answer 14

radio, micro, infered, visible light, UV, X-ray, gamma ray

Question 15

light bends ______ from the normal as it speeds up

Answer 15

away