Einstein and the Photoelectric Effect (1 Viewer)

[Xtrinsic_Psycho]

"Outline Einstein's explanation of the photoelectric effect" [5 Marks]

can some1 plz help me out with this question? I can never seem to get full marks for this question...
can anyone first explain to me Einstein's contribution to the photoelectric effect and then explain what would be the general requirement for full marks in this question?

thx in advance

 

[Constip8edSkunk]

having a punt at the mark spread

- talk about einstein's generalisation of plancks theory to light... ie light can be quantised through discrete packets of photons (~1 mark (estimate))

- describe properties of photons, eg. relations with frequencies, intensity(amplitude) (~1maks)

- link above properties with observations concerning photoelectric effect
(eg. assumptions(1 mark), why electrons are released based on frequency of light (not intensity) (1 mark), behaviour of ejected electrons (1 mark), ) and another mark mixed in somewhere

 

[Xtrinsic_Psycho]

hey thx Constip8edSkunk =)
At least now i have a starting block to work on
Anyone other guys that can help me with that question?

 

[joshhopp]

to get full marks youd really need to discuss threshhold frequency, work function, and the max kinetic energy of the photoelectron. ie, electrons are only emitted if the threshhold frequency is satisfied, and the energy of the photoelectrons is given by E = hf = workfunction + kineticenergy

 

[joshhopp]

to get full marks youd really need to discuss threshhold frequency, work function, and the max kinetic energy of the photoelectron. ie, electrons are only emitted if the threshhold frequency is satisfied, and the energy of the photoelectrons is given by E = hf = workfunction + kineticenergy

 

[Tommy_Lamp]

basically comes down to E = hf - W
hf must be greater then W to produce any energy
since h is a constant f is the value that must be higher then W

this is the threshold frequency

thats pretty much it

 

[rumour]

I had the same question in my trial, but I didn't get full marks

Would putting the graph in be a good idea?

 

[Constip8edSkunk]

yes, graphs are always useful, it can dramatically reduse the verbosity of your explaination

 

[Tommy_Lamp]

picture/equation = 1000 words

 

[Suvat]

I was never able to separate einstein's explanation of the photoelectric effect with the black body effect, it's basically the same concept - energy must be absorbed and distributed in packets.

Now to expand that into an 8 mark exam response is the hard part, I used to be able to do it...

 

[Xtrinsic_Psycho]

thx a bunch guys
really appreciate it

 

[The Bograt]

always use equations when you can, eg question about torque, write down the equation and explain everything after.

Also, my teacher told me that if the question says 'explain' then you should try draw a diagram - eg for how Thompson measured the charge/mass ratio of an electron