Physics Exam Thoughts (3 Viewers)

[Exp]

X was alpha because they produce short and thick tracks(hence why it was in bold)
Y was beta as they produce long and thin tracks.

but doesn't the cloud chamber rely on the degree of ionisation, and so alpha would have the longest path since highest ionisation as opposed to beta?

 

[Drdusk]

but doesn't the cloud chamber rely on the degree of ionisation, and so alpha would have the longest path since highest ionisation as opposed to beta?

It relies on the particle ionizing the water vapor around it. Alpha particles are really highly ionizing hence they don't make it much past where they're generated(hence their path is short).

Beta particles are much less ionizing and hence similarly their paths are long

 

[782341]

Am i the only one that didnt find the exam as easy as everyone is making it out to be? Did medical physics option btw

 

[Drdusk]

Am i the only one that didnt find the exam as easy as everyone is making it out to be? Did medical physics option btw

Maybe your option topic was harder? who knows.
It might get aligned better than us easy goers who did Q2Q

 

[i love maths]

Am i the only one that didn't find the exam as easy as everyone is making it out to be? Did medical physics option btw

I also did medical and thought some of the questions were a bit hard. MC was super tough and there wasnt a single question on any of the scientists in ideas to implementation. Wasted 2 days of studying all that.

 

[bjw22]

Nice and straightforward - I thought medical physics was pretty good too.
What was the velocity of the projectile on the moon - I did it wrong and got 400ms^-1?
For anyone who did medical physics, the thing about compare ultrasound A and B, was it right to say that they will both be reflected in the same proportion because the boundary was the same regardless of which side they approached from??

 

[Drdusk]

Nice and straightforward - I thought medical physics was pretty good too.
What was the velocity of the projectile on the moon - I did it wrong and got 400ms^-1?
For anyone who did medical physics, the thing about compare ultrasound A and B, was it right to say that they will both be reflected in the same proportion because the boundary was the same regardless of which side they approached from??

Yep I also got around 400, I think 464 to be exact.
Delta(KE) = -Delta(EP) was my method

 

[i love maths]

Yeah i think thats right for the medical question, thats what I said. and i also got 400ms^-1 cause i tried to do suvat

 

[bjw22]

Yep I also got around 400, I think 464 to be exact.
Delta(KE) = -Delta(EP) was my method

Lol idk what I was doing, I found the acceleration and then subbed it into a projectile motion equation - knew it was wrong at the time too given that acceleration isn't constant at all heights so ripppp

 

[782341]

Yep I also got around 400, I think 464 to be exact.
Delta(KE) = -Delta(EP) was my method

I also got 464 but ive heard from people that this was the wrong answer

 

[i love maths]

You had to do the a change in GPE = kinetic energy, so then the change in GPE that we worked out you equate to 1/2 *mv^2

 

[Drdusk]

I also got 464 but ive heard from people that this was the wrong answer

They be trippin haha

It has to be, what method did they use?

 

[782341]

They be trippin haha

It has to be, what method did they use?

I think they used delta ke=delta gpe instead of -delta gpe

 

[Drdusk]

I think they used delta ke=delta gpe instead of -delta gpe

Yep that's definitely wrong. I initially did that accidentally.
Using that you get a velocity that's greater than the initial velocity. It is losing KE as it gains EP when it goes higher.
Hence the final velocity must be less!

 

[Exp]

would the b6 cut off be around 85?

 

[bjw22]

would the b6 cut off be around 85?

I reckon maybe about there comparing rawmarks.info, it seems easier than some past papers in parts so that should be about right - a tad higher perhaps if NESA be cruel.

 

[supR]

Would you not just derive orbital velocity from centripetal force = gravitational force? Then get 1480ms^-1? OOOOH was it not asking for orbital velocity?

See overall, I thought the paper was conceptual and actually difficult, but if you are a "good student" you wouldn't have gotten fucked over like 2017 last q would've fucked most students regardless of your ability, study preparation etc. This paper really favoured students who studied, as you'd struggle otherwise ~ Gravitional vs electric definition, photocell and solar cell, electricity in the home and the projectile error and velocity questions were all quite conceptual, and I'd argue they are difficult. Although I think I got them all quite well, except the electricity one xP

 

[Shadowfaxx]

Whoa what an interesting and challenging test that challenges us in unique and reasonable ways.
(Insert multiple choice and graph question)
NESA - "Hahahaha lets make the cut-off 90'
For velocity, did anyone get 1122ms?

 

[maxcf212]

Would you not just derive orbital velocity from centripetal force = gravitational force? Then get 1480ms^-1?

See overall, I thought the paper was conceptual and actually difficult, but if you are a "good student" you wouldn't have gotten fucked over like 2017 last q would've fucked most students regardless of your ability, study preparation etc. This paper really favoured students who studied, as you'd struggle otherwise ~ Gravitional vs electric definition, photocell and solar cell, electricity in the home and the projectile error and velocity questions were all quite conceptual, and I'd argue they are difficult. Although I think I got them all quite well, except the electricity one xP

It's not orbital velocity though. It was vertical velocity only right?

 

[Exp]

Whoa what an interesting and challenging test that challenges us in unique and reasonable ways.
(Insert multiple choice and graph question)
NESA - "Hahahaha lets make the cut-off 90'

lol I hope not