Graphs and Diagrams.. (1 Viewer)

[香港!]

When do you know to chuck in a diagram???
In my trials it was so bs.. there was a question just saying compare two things.. it was 4 marks.. and in the marking criteria it says for full marks you need "4 statements+graph with values".
It never said to draw a graph anywhere..
lol wtf?
even if i wrote 4 statements still can't get full marks??

 

[Captain Gh3y]

Tables and graphs are always good when the question asks you to compare.

Other than that, in any question where you're asked to describe something you can physically draw (maybe a motor, cathode ray tube, loudspeaker, experimental apparatus, whatever) a diagram always looks good if it's drawn neatly, and they can in fact be worth marks if they are relevant.

 

[spank_meh]

Tables and graphs are always good when the question asks you to compare.

Other than that, in any question where you're asked to describe something you can physically draw (maybe a motor, cathode ray tube, loudspeaker, experimental apparatus, whatever) a diagram always looks good if it's drawn neatly, and they can in fact be worth marks if they are relevant.

So they can take marks of you if you don’t draw diagrams /or make tables?

 

[香港!]

^ well in my trials, according to the marking criteria you CAN'T get full marks in that question if you didn't have that graph, even though the question never even hinted to draw a graph..
damn dis physic so stupid lolz

 

[Captain Gh3y]

That's a bit odd if the question doesn't say so anywhere. I don't think that'd happen in the HSC, if you needed one they'd say so.

 

[richz]

wat q was that, was it comparing the generators or wateva it was?

 

[spank_meh]

damn dis physic so stupid lolz

hahah yeah i agree with you on this one dude... hmmm that was unfair but why did they take the marks of if they didnt even mention the necesity of graph in the question??? we do not have antenas to detect what markers think the right answer should be, or do we??? .... that sucks but.....

 

[helper]

Without seeing the question, its hard to say.
There might have been an implicit reference to a graph.
Eg Compare the current output from an AC and DC generator.

Normally in the HSC, if they require a graph or diagram it will be explicitly mentioned.
The only exception to that is show all working which is written in the instructions.

However, remember a diagram is worth a thousand words, so use diagrams, tables, graphs, equations etc to help in your answer as much as possible.

 

[香港!]

wat q was that, was it comparing the generators or wateva it was?

Here it is:
"Compare the strong nuclear and electrostatic forces acting in the nucleus".
Now I don't see the need for drawing a "graph with values" to do that???

 

[helper]

Nothing saying you have to there but I can see why they expected one.
In the HSC, it probably would say a concise, thorough comparison.

Under that description, it would have been easier to gain full marks with a graph but it wouldn't be compulsory.

 

[香港!]

How do you draw a graph with values to "Compare the strong nuclear and electrostatic forces acting in the nucleus"?

Havent seen one before -_-

can sum 1 show me plz

 

[thunderdax]

Just draw the graph of the strong nuclear force (starts repulsive passes x axis hits a turning point and goes back to zero) and on the same graph draw the electrostatic one (ie a hyperbola y=1/x sort of thing.)

 

[Captain Gh3y]

Heh, I was just studying that dotpoint. The graph in the notes I'm using looks like this if Captain Gh3y were to draw it in paint:

And the notes add:

When the nucleons are very close (< ~ 0.5x10-15 m) the force is strongly repulsive. The force then becomes attractive at separations for a range between ~ 1x10-15 and 2.3x10-15 m, with a maximum attraction at a certain distance (~ 1.3x10-15 m). Outside this range the force is repulsive.

 

[KFunk]

I don't think the nuclear force becomes repulsive again at larger distances - I'm pretty sure it's just very localised (partly explained by the pion transfer theories) and so it just kind of fades off. If it became repulsive like that then neutrons wouldn't be useful probes or for fission 'cause, given the strength of the strong force, it would never get close to a nucleus. I think it's more like this:

 

[thunderdax]

Hey KFunk, why do you have energy on the y-axis on your graph. I know they are kind of related, but shouldn't it be force?
Also, to answer this question I think you would also need the electrostatic force graph there too.
Edit: Also, nice graph, that's exactly what it looks like.

 

[Captain Gh3y]

I found that part about the nuclear force becoming repulsive again strange, never heard of that before. The picture I posted represents the net force on the nucleons taking distance into account, though; somewhere after the point where dE/dr > 0 on your image is where the coulombic force becomes greater.

 

[KFunk]

Ahh, that makes more sense then. I reckon you'd be safer in drawing the graph of either force separately because the net force logic only works between two protons (so you'd end up having to draw another diagram to make it relevant to neutrons :-S).