Please help me answer this question. (1 Viewer)

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Question (17) 6 Marks

Explain the particle theory of light in terms of photons with particular energies and frequencies and how it can explain the photo electric effect.

PLEASE GIVE ME A PERFECT ANSWER, PLEASE. HOW CAN I GET THE 6 MARKS?

 

[llllllllllll]

The thing is that in the jacaranda textbook it is like 4-5 pages to explain this and in the test I need to write like half a page, so what should I write for 6 marks?

 

[Fizzy_Cyst]

- Light consists of particles (photons)
- The energy of the photon depends on the frequency of the light (E=hf)
- PE Effect is when electrons are liberated from a metal surface when light of suitable frequency is shone on it
- Classical physics suggested that light of any frequency could liberate electrons as energy of electrons would gradually build up
- Classical physics also suggested that if you increased the intensity of the incident light source, photoemission would occur quicker
- The two above predictions of classical physics did not occur within the experiment
- It was noticed that light had to be above a minimum 'threshold' frequency in order for photoemission to occur (regardless of intensity)
- This was explained by Einstein and how light existed as a quanta of energy (photon) and if the energy/frequency of this photon (E=hf) was high enough to overcome the electrons attraction to the nucleus (work function), then the photoelectron would be liberated instantaneously
- Seeing as this is a 1:1 interaction, intensity has no effect on whether a photoelectron will be emitted as the energy of each incident photon must be above the work function of the metal
- if energy of photon > work function, intensity determines how many electrons are emitted (photocurrent)

Something like that

 

[llllllllllll]

Thanks a lot man, all I have to do now is put everything together as apparently they award 1 mark to how your response flows, or that's only how my teacher marks it...

 

[iSplicer]

- Light consists of particles (photons)
- The energy of the photon depends on the frequency of the light (E=hf)
- PE Effect is when electrons are liberated from a metal surface when light of suitable frequency is shone on it
- Classical physics suggested that light of any frequency could liberate electrons as energy of electrons would gradually build up
- Classical physics also suggested that if you increased the intensity of the incident light source, photoemission would occur quicker
- The two above predictions of classical physics did not occur within the experiment
- It was noticed that light had to be above a minimum 'threshold' frequency in order for photoemission to occur (regardless of intensity)
- This was explained by Einstein and how light existed as a quanta of energy (photon) and if the energy/frequency of this photon (E=hf) was high enough to overcome the electrons attraction to the nucleus (work function), then the photoelectron would be liberated instantaneously
- Seeing as this is a 1:1 interaction, intensity has no effect on whether a photoelectron will be emitted as the energy of each incident photon must be above the work function of the metal
- if energy of photon > work function, intensity determines how many electrons are emitted (photocurrent)

Something like that

A diagram/flowchart would greatly help, and using dot points is also a good idea.

And no, I've heard that one mark isn't "allocated" to flow, but they can deduct a mark earnt elsewhere if your answer is overly verbose and is all over the place. Also, one mark gone for each contradiction.

 

[llllllllllll]

Thank you too iSplicer.

 

[Fizzy_Cyst]

And no, I've heard that one mark isn't "allocated" to flow, but they can deduct a mark earnt elsewhere if your answer is overly verbose and is all over the place. Also, one mark gone for each contradiction.

For the higher mark questions, the band 5/6 responses must 'demonstrate coherence and logical progression'

Example, if you draw a diagram and then talk about the diagram, it is logical progression. If you talk about the diagram and draw it further down the page, it is not logical progression and you will get marked down for it. Stupid, but that is what happens!

You will see this in marking schemes (eg, the 6 mark question in 2011 HSC), also even if it isnt directly in the marking scheme, it is one of the criteria which students must meet to be awarded a Band 6. Same as significant figures, not in marking schemes, but one of the things which 'judges' look for in a band 6 student

As iSplicer said -- dot points are your friend Even for the higher mark questions, you can still demonstrate coherence and logical progression from correctly sequenced dot points

 

[llllllllllll]

Guys, since you are so good at physics can you please please please answer this, please. I really need a good answer for this question.

Outline plank's observations and explanations of the black body radiation and his hypothesis as to the source of black body radiation. 6 marks.

Can anyone give me a good answer? Please.

 

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[qwerty44]

Why don't you try, and then put it up for someone to look at instead of asking for a straight answer?

 

[Alkenes]

+1

Why don't you try, and then put it up for someone to look at instead of asking for a straight answer?

 

[RishBonjour]

In the HSC exam, are we allowed to write in dot points, not as in like "photon's energy is directly proportional to its frequency (E=hf)"
but , like, talk about one part of the question and then a little dash in the next line and start the other.

Also, how would you draw a diagram for OP's original question?

EDIT: read Fizzy_cyst's post..

 

[llllllllllll]

I have english test tomorrow Memorising my essay... That's why I couldn't right one.
The thing I'm confused with is how does the intensity/wavelength graph relate to planks explanations, that energy is quantised. He observed that classical physics could not explain the results from the induction furnace experiment and that the classical graph violates the law of conservation of energy etc... but how does plank's explanation explain this situation?