Physics Predictions/Thoughts (3 Viewers)

[C2H6O]

Can we simply state x=L.m.lamda/d

im not sure id think its probably fine but the derivation isnt that hard, if you have , you can approximate for small order maxima cause the angle is small and then use to get

 

[C2H6O]

What in the actual crazy are you guys talking about?? Where did you all learn this?? I've never heard of any of it before, is it in the syllabus? And how are we expected to think of this in the exam? Just whaaaaaaat?!

nah it was one niche obscure q20 multi

 

[BionicMango]

Can we simply state x=L.m.lamda/d

Maybe but I would definitely avoid stating it outright, do what C2H6O said (or something along those lines) so that if you get the calculations wrong you will still get some marks.

 

[barnyard]

Can we simply state x=L.m.lamda/d

yea if u say dsin=mlambda then say since theta is small small angle approximation lets u sub in sin=x/L

 

[BionicMango]

What in the actual crazy are you guys talking about?? Where did you all learn this?? I've never heard of any of it before, is it in the syllabus? And how are we expected to think of this in the exam? Just whaaaaaaat?!

It was a strange questions that probably should have specified something along the lines of “the velocity of galaxies as currently observed” or smth. Basically, the galaxy is expanding, so galaxies farther away move away from us at a faster rate. But the light that we receive really just gives us a snapshot of the past - the light takes longer to reach us, and therefore represents a galaxy etc. as it was in the past, so the red shift will be less strong even though it is faster because it tells us about the past, not the present.

With astronomical sizes such as these the fact that the speed of light is finite means that we are ALWAYS looking at the past. That’s why astronomy is important - we get to see into the distant past even though we’re not actually in it, which can tell us a lot about our universe when it was younger!

 

[alphxreturns]

Can we simply state x=L.m.lamda/d

dont assume its small angle its alot safer to do it the normal way, if ur doing proportional stuff then work with sinø increase = tanø increase i reckon

 

[BionicMango]

dont assume its small angle its alot safer to do it the normal way, if ur doing proportional stuff then work with sinø increase = tanø increase i reckon

Or just use tan(arcsin(theta)).

if you haven’t seen the derivation if dsin(theta) = m*lambda I would, because it relies on the fact that theta is very small already. So if the angle is not sufficiently small the formula itself won’t work that well either.

 

[Trial&Error]

What's the rule for significant figures in physics? Is it just to put the lowest in the question like chemistry or are they more lenient? Because I've seen some questions where the lowest sigfig is 1 which is quite impractical to leave your answer in.

 

[C2H6O]

What's the rule for significant figures in physics? Is it just to put the lowest in the question like chemistry or are they more lenient? Because I've seen some questions where the lowest sigfig is 1 which is quite impractical to leave your answer in.

not assessable i believe but best to work with 3dp always so no mistakes cause some calculation questions might have a range of acceptable error depending on your method and rounding errors. i dont believe the answer's dp/sf matters, i usually leave 2dp for consistency

 

[lawfirm]

At one stage I had an option to drop this

 

[splatcat]

not assessable i believe but best to work with 3dp always so no mistakes cause some calculation questions might have a range of acceptable error depending on your method and rounding errors. i dont believe the answer's dp/sf matters, i usually leave 2dp for consistency

I think they usually check one question for correct significant figures but you don't know which, so just leave it as lowest in question. If its something inconvenient like 1, give more and then a rounded final answer specifying that you rounded to 1 is probably good enough

 

[Tony Stark]

What's the rule for significant figures in physics? Is it just to put the lowest in the question like chemistry or are they more lenient? Because I've seen some questions where the lowest sigfig is 1 which is quite impractical to leave your answer in.

I believe we are expected to use the amount of siginicant figures of the variables we are given. For example, if we are given time of 1.234 seconds then we should probably keep consistency by giving our answer (let's say the quesiton is asking for distance) to 4 significant figures for example 38.77 ms.

 

[splatcat]

I believe we are expected to use the amount of siginicant figures of the variables we are given. For example, if we are given time of 1.234 seconds then we should probably keep consistency by giving our answer (let's say the quesiton is asking for distance) to 4 significant figures for example 38.77 ms.

And remember the significant figures of stuff on the formula sheet. Things like gravity are only 2 whereas some are 4

 

[C2H6O]

I think they usually check one question for correct significant figures but you don't know which, so just leave it as lowest in question. If its something inconvenient like 1, give more and then a rounded final answer specifying that you rounded to 1 is probably good enough

i swear thats only assessable in chem. i havent seen it in any of the hsc criterias 2019-2024. closest was range of error and that was like value must be between 4.20 and 4.10 or something (sig figs not mentioned)

 

[Trial&Error]

i swear thats only assessable in chem. i havent seen it in any of the hsc criterias 2019-2024. closest was range of error and that was like value must be between 4.20 and 4.10 or something

I guess it's better to be safe than sorry. We might as well give our answer twice: once as normal 3-4 sigfigs and then again rounded to the lowest in the question.

 

[BionicMango]

What's the rule for significant figures in physics? Is it just to put the lowest in the question like chemistry or are they more lenient? Because I've seen some questions where the lowest sigfig is 1 which is quite impractical to leave your answer in.

Lowest out of every value you use unless it’s a discrete value like number of people etc. (usually never).

If it is only 1sf then just do 2sf, it is very likely not assessed in that question then anyway

 

[louieiscooked]

i js realised why this course is taught over 2 years and not 2 days

 

[BionicMango]

Honestly those that are curious enough to go beyond the syllabus to answer their questions are in the best position both in the hsc and afterward if they pursue a related career, there’s so much to physics that even though the course feels too full in year 12 it doesn’t even scratch the surface.

 

[BionicMango]

Maybe it would be better if we actually did any physics in year 9-10 (aside from just energy transformations)

 

[chikki7]

hey team for this question, does the can rotate cos the force it imposes on the magnet has an equal and opposite reaction back on the can??