Physics Predictions/Thoughts (8 Viewers)

[abelsj01]

why can't u find the find using change in GPE ie dU = GMm(1/ri-1/rf)

idk u probs can but i had to learn the whole syllabus over two days so my knowledge defo isnt the best but as far as the r value in calculations is it r = altitude of orbit + radius of earth or just r = altitude of orbit?

 

[yleeey]

View attachment 41318

anyone know what formula to use for this question?

ahh i forgot to convert km to m

 

[carrotsss]

idk u probs can but i had to learn the whole syllabus over two days so my knowledge defo isnt the best but as far as the r value in calculations is it r = altitude of orbit + radius of earth or just r = altitude of orbit?

it’s because they said radius in the question, you’d add them if they said altitude

 

[Jimmwhitt]

it’s because they said radius in the question, you’d add them if they said altitude

Wouldn't it be the other way around? Considering altitude is distance above the surface and radius is distance from the centre of the Earth.

 

[carrotsss]

Wouldn't it be the other way around? Considering altitude is distance above the surface and radius is distance from the centre of the Earth.

what I was saying is the radius is just the radius, whereas the radius when you’re given altitude is altitude+earth radius

 

[abelsj01]

does anyone recognise the double slit formula x = λL/d? i can't find it on any hsc resource but i was taught it earlier this year from my teacher. all i can find is dsintheta = mλ or dsintheta = (m+1/2)λ. is that formula just a derivation of one of the two other formulas?

 

[Hudz777]

does anyone recognise the double slit formula x = λL/d? i can't find it on any hsc resource but i was taught it earlier this year from my teacher. all i can find is dsintheta = mλ or dsintheta = (m+1/2)λ. is that formula just a derivation of one of the two other formulas?

think about what sintheta actually is…
for small angles, sintheta approximately is equal to tantheta, so we just say it’s the fringe separation on the length. then you get your formula xx

 

[abelsj01]

think about what sintheta actually is…
for small angles, sintheta approximately is equal to tantheta, so we just say it’s the fringe separation on the length. then you get your formula xx

true but it becomes less and less accurate as the angle gets bigger so is there not a better way for those instances?

 

[Hudz777]

true but it becomes less and less accurate as the angle gets bigger so is there not a better way for those instances?

mmm, not sure tbh, that’s just what i was taught, good question though

 

[salihaaaameeer]

Oh god. Module 8 is awful. The textbook is awful. Please give good resources

science ready can quite literally move you up at least 1 band if you watch their videos

 

[abelsj01]

science ready can quite literally move you up at least 1 band if you watch their videos

on jah science ready is saving my whole atar rn

 

[salihaaaameeer]

what were the 2 postulates from plancks discovery?

planks postulates are that energy is absorbed and emitted in discrete packets called quanta with the energy E = hf discontinuously, and according the wavelength max = b/T, the temperature of a blackbody is inversely proportional to its max wavelength, that is the lower the wavelength the higher its temperature.

there's also bohrs postulates on electron orbits
1. electron orbits remain in a fixed position or orbital without the emission of EM radiation
2. electrons can move up and down these orbits according to the energy differences between these orbits (E =hf --> need a certain frequency of light/threshold frequency to be able to do so).

and Einsteins postulates on the photo electric effect which states that there is a certain threshold frequency which needs to be present in light incident on a surface for that surface to emit an electron form its surface known as the work function, and that the intensity of light increases the amount of electrons that are emitted as long as its above that frequency, also increasing frequency of light will maximise the kinetic energy of the emitted electrons. there's a formula specifically for Einsteins one so u don't need to memorise it

 

[Hudz777]

true but it becomes less and less accurate as the angle gets bigger so is there not a better way for those instances?

here are some things i found - i don’t think you are going to encounter a large enough angle in double-slit for the equivalence to be incorrect.

 

[Hudz777]

here

 

[liamkk112]

here are some things i found - i don’t think you are going to encounter a large enough angle in double-slit for the equivalence to be incorrect.

if u get given a diffraction grating the angles become larger, in that case i would manually compute theta using tan and then sub that into dsin = m lambda

 

[Hudz777]

if u get given a diffraction grating the angles become larger, in that case i would manually compute theta using tan and then sub that into dsin = m lambda

mm yeah, that’s probably a good idea

 

[ghreysantomy]

Can anyone help me with Q20 of the 2022 paper please?

 

[carrotsss]

Can anyone help me with Q20 of the 2022 paper please?

P is turning against the motion, it’s not actually moving itself at all at that very instant.

 

[salihaaaameeer]

Can someone please explain this, im so confused! its about the diffraction experiment

 

[carrotsss]

View attachment 41326
Can someone please explain this, im so confused! its about the diffraction experiment

Don’t overcomplicate it, just use the formula on the formula sheet