***2015 LC Physics - June 15th***

Chocolalla

Anyone do question eleven?

AMDD

Chocolalla wrote: »

Anyone do question eleven?

Yep

Chocolalla

AMDD wrote: »

Yep

Lol Answers pls

blue_velvet

Chocolalla wrote: »

Anyone do question eleven?

I did! How did you define the Tesla?

AMDD

Chocolalla wrote: »

Lol Answers pls

(a) Tesla I wasn't too sure. I just used the formula saying it's the ratio of the work function to the area.
(b) A.C I believe is a sin wave and D.C I believe is the same except you don't include beneath 0.
(c) Electromagnetic induction I said is when an EMF is induced due to the change in magnetic field linking a circuit.
(d) I believe this is to do with inducing an EMF which D.C wouldn't do. Wasn't too sure on this.
(e) I said with low voltage this means there's a smaller current according to Ohm's Law which means there is less charge per second.
(f) Subbed into formula
(g) Just said A.C is constantly changing so you need an RMS value to compare.
(h) Advantage: Environmentally friendly
Disadvantage: Expensive

Looking back, I actually think I answered this question pretty badly, haha, at least it was an extra question.

Chocolalla

AMDD wrote: »

(a) Tesla I wasn't too sure. I just used the formula saying it's the ratio of the work function to the area.
(b) A.C I believe is a sin wave and D.C I believe is the same except you don't include beneath 0.
(c) Electromagnetic induction I said is when an EMF is induced due to the change in magnetic field linking a circuit.
(d) I believe this is to do with inducing an EMF which D.C wouldn't do. Wasn't too sure on this.
(e) I said with low voltage this means there's a smaller current according to Ohm's Law which means there is less charge per second.
(f) Subbed into formula
(g) Just said A.C is constantly changing so you need an RMS value to compare.
(h) Advantage: Environmentally friendly
Disadvantage: Expensive

Looking back, I actually think I answered this question pretty badly, haha, at least it was an extra question.

No I think your answers are good , for tealsa since it said magnetic flux I just gave the def I don't think I'm right thou

Chocolalla

blue_velvet wrote: »

I did! How did you define the Tesla?

I just gave the def for magnetic flux, u?

blue_velvet

AMDD wrote: »

(a) Tesla I wasn't too sure. I just used the formula saying it's the ratio of the work function to the area.
(b) A.C I believe is a sin wave and D.C I believe is the same except you don't include beneath 0.
(c) Electromagnetic induction I said is when an EMF is induced due to the change in magnetic field linking a circuit.
(d) I believe this is to do with inducing an EMF which D.C wouldn't do. Wasn't too sure on this.
(e) I said with low voltage this means there's a smaller current according to Ohm's Law which means there is less charge per second.
(f) Subbed into formula
(g) Just said A.C is constantly changing so you need an RMS value to compare.
(h) Advantage: Environmentally friendly
Disadvantage: Expensive

Looking back, I actually think I answered this question pretty badly, haha, at least it was an extra question.

for (e) I said low voltage means larger current which leads to greater power loss and then I explained with reference to Joule's Law P=I^2R and P=VI

AMDD

Chocolalla wrote: »

No I think your answers are good , for tealsa since it said magnetic flux I just gave the def I don't think I'm right thou

I think I may have snuck in the definition for that also since I just decided to write all that I knew, don't think they will mark me down for having extra, even if it isn't right.

AMDD

blue_velvet wrote: »

for (e) I said low voltage means larger current which leads to greater power loss and then I explained with reference to Joule's Law P=I^2R and P=VI

Hmm, that sounds better, I thought I should have fit in Joule's Law in there somewhere.

SteveZissou

Chickennuggets wrote: »

I got .79Mev

Actually I think I got that as well, couldn't remember! Thanks:)

blue_velvet

AMDD wrote: »

Hmm, that sounds better, I thought I should have fit in Joule's Law in there somewhere.

I was unsure as to whether to make reference to the written text above in some of my answers or not??

AMDD

blue_velvet wrote: »

I was unsure as to whether to make reference to the written text above in some of my answers or not??

Oh ****, I just realised that I didn't even look at that, that's so dodge haha.

Chickennuggets

Benm123 wrote: »

I also got an answer like that but then went back and realised I forgot to sqaure the speed of light! I them re did it and squared the speed of like and got 511MeV which seemed like a much nicer answer

Im 90% I squared the speed

blue_velvet

Chocolalla wrote: »

I just gave the def for magnetic flux, u?

Is Tesla not the unit for magnetic flux density? I said magnetic flux÷Area=magnetic flux density and then drew a diagram showing area and magnetic field lines..I think I said something about the magnetic flux density being the number of magnetic field lines falling perpendicularly??

Benm123

Chickennuggets wrote: »

Im 90% I squared the speed

Hmm.. This is confusing me.
I did
E=Mc^2
Taking m as mass of electron
And c as speed of light
Then put my value for over eV.

I got 510.99 MeV then which rounded to a nice 511, which seemed like a more suitable answer than them asking for mega electron volts and then having a 0.something answer.
But I'm doubting myself now that others have said they also got 0.something MeV

Also, coming out of the exam my friend who usually gets A1's said he got 0.something but then I asked did he square the speed of light and he said ohhhh **** no he didn't.
What did anyone else get?

blue_velvet

For the resistance of a metallic conductor experiement what did people say was the rate of change of resistance?was it just the slope?

AMDD

blue_velvet wrote: »

For the resistance of a metallic conductor experiement what did people say was the rate of change of resistance?was it just the slope?

Didn't do it but pretty sure that's right.

uzpuz

I put in 4180 for specific heat capacity for polystyrene but I knew it was wrong.
However I ended up getting 2.3 by 10 to power 6 which is the latent heat of vaporisation as stated in previous marking schemes

Chocolalla

blue_velvet wrote: »

Is Tesla not the unit for magnetic flux density? I said magnetic flux÷Area=magnetic flux density and then drew a diagram showing area and magnetic field lines..I think I said something about the magnetic flux density being the number of magnetic field lines falling perpendicularly??

I just thought of the magnetic flux def which is magnetic flux density by area i think will get attempt marks hopefully

uzpuz wrote: »

I put in 4180 for specific heat capacity for polystyrene but I knew it was wrong.
However I ended up getting 2.3 by 10 to power 6 which is the latent heat of vaporisation as stated in previous marking schemes

I think I did that as well

blue_velvet

Chocolalla wrote: »

I just thought of the magnetic flux def which is magnetic flux density by area i think will get attempt marks hopefully

I'd say you will don't worry!

Jammysticks

Does anybody know what the circuit diagram for the Q4 expt was?

Seannyyboy

What did people get for the assumptions for the polystyrene cup? (Q,2)
I said that it had negligible heat capacity and that it's a perfect insulator (ie. No heat loss)

Benm123

Jammysticks wrote: »

Does anybody know what the circuit diagram for the Q4 expt was?

Yeah it was the circuit with a power source, potential divider/rheostat, ammeter, voltmeter and then filament bulb!
It was the basic circuit you use for the other IV graph experiments

2345

What are standing waves and how do they occur

Seannyyboy wrote: »

What did people get for the assumptions for the polystyrene cup? (Q,2)
I said that it had negligible heat capacity and that it's a perfect insulator (ie. No heat loss)

yep i think thats it
NO heat loss to surrounding
and cup doesnt absorb any heat

The_N4sir

Benm123 wrote: »

Hmm.. This is confusing me.
I did
E=Mc^2
Taking m as mass of electron
And c as speed of light
Then put my value for over eV.

I got 510.99 MeV then which rounded to a nice 511, which seemed like a more suitable answer than them asking for mega electron volts and then having a 0.something answer.
But I'm doubting myself now that others have said they also got 0.something MeV

Also, coming out of the exam my friend who usually gets A1's said he got 0.something but then I asked did he square the speed of light and he said ohhhh **** no he didn't.
What did anyone else get?

I got around 510/520 something electron volts aswell. It was a big number so i don't remember exactl. Should get some marks if it is wrong anyway

uzpuz

Did anyone do applied electricity apart from me?

Hon the Dubs

Benm123 wrote: »

Hmm.. This is confusing me.
I did
E=Mc^2
Taking m as mass of electron
And c as speed of light
Then put my value for over eV.

I got 510.99 MeV then which rounded to a nice 511, which seemed like a more suitable answer than them asking for mega electron volts and then having a 0.something answer.
But I'm doubting myself now that others have said they also got 0.something MeV

Also, coming out of the exam my friend who usually gets A1's said he got 0.something but then I asked did he square the speed of light and he said ohhhh **** no he didn't.
What did anyone else get?

I can't remember if I squared it or not now you've put doubts in my mind :P but I got 0.79 MeV

Seannyyboy

What are standing waves and how do they occur?

Cr4pSnip3r

Looking for a C3/C2 with how that went. Tbh, that'd be fine with me. Looking for 400 points overall and if I don't fail maths then it should get to about that.