June 2011 G485-Fields, Particles and Frontiers of Physics

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Original post by Sail2011

i got 87 lol, and yh same i recon i did okay, but there wasnt anyhthing on decay reactions - i could have done that lol

i got 18 as well!! i did it by simutaneous equations... resolving forces...took me a while but i got there in the end =)

Reply 961

yu80359

I used material U238 is that right I think should be U235 for fission?

Reply 962

charlottehunt

Original post by Captain Hob

How did people get the angle for the ball question as 18? I got 73 using the tan of the angle and the horizontal/vertical components.

Overall, a tricky paper. Took a while to figure out some of the answers, but I think I did okay.

I got 73 aswell, hopefully i'll get some marks if it is wrong :s-smilie:

Reply 963

Oh my Ms. Coffey

Original post by yu80359

I used material U238 is that right I think should be U234 for fission?

U235 is used for fission, U238 is there but isnt used.

Reply 964

Franklin

Original post by lpmad

Using the left had rule force would be downwards and therefore the magnet would be pushed upwards therefore you would take it away from the balance

No.

left hand rule uses direction of conventional current and therefore giving the force upwards

Reply 965

In the looney bin

Original post by yu80359

I used material U238 is that right I think should be U235 for fission?

Idk what your on about, i said Boron rods, as they are used to control the chain reaction by absorbing neutrons.

edit: Wait what didn't it say a material used in controlling the reaction or something?

Dno what i was writing about then :tongue:

(edited 12 years ago)

Reply 966

Captain Hob

Original post by ViralRiver

I got 18.4 degress for the angle. Resolved vertically and horizontally, then divided through to get rid of tension.

Tension! I knew I'd forgotten something. I actually thought about it, then forgot to stick it in. Ah well, ecf I hope.

Reply 967

ViralRiver

I realised at the end that they couldn't give 2 marks for a simple V=IR - so actually read the question. I think I got an answer of less than one for power dissipated - using P=IV using calculated current and 0.2V.

Did anyone else get like 4. something times 10 to the 7 or so for the magnitude of velocity for the electric? field question? I thought it was a bit unfair to give 1 mark and no space for the suvat questions above it though... Then I used that velocity in 1/2mv^2 with 9.11x10^-31 to work out Ek.

Reply 968

susan23

ohh no I got the magnet Qs wrong :cry2:

not fair...I proper used the left hand and everything..what direction was the force? I said onto the scale... :cry2:

and then I added that to 2.5 :cry2:

fml.

Reply 969

sam1am

When it asked for the three forces that act on protons and neutrons....

I used strong, weak and gravitational as I reasoned that the electrostatic force does not act on protons! Not sure if that's right though.

Also got 3 for the capacitor ratio, very unsure about it though....

Edit: typo - I meant the electrostatic force does not act on neutrons

(edited 12 years ago)

Reply 970

yu80359

F**K I said U238 instead of U235 I think I only lost one mark for that?

Reply 971

ViralRiver

Original post by In the looney bin

Idk what your on about, i said Boron rods, as they are used to control the chain reaction by absorbing neutrons.

If you're talking about the moderator question, I said graphite. Boron is for control rods.

Reply 972

trapzbrah

Original post by susan23

ohh no I got the magnet Qs wrong :cry2:

not fair...I proper used the left hand and everything..what direction was the force? I said onto the scale... :cry2:

and then I added that to 2.5 :cry2:

fml.

was the force down?

Reply 973

susan23

Original post by sam1am

Bt elecetrostatic replusion forces with protons though? :colondollar:

Reply 974

Oh my Ms. Coffey

Original post by ViralRiver

If you're talking about the moderator question, I said graphite. Boron is for control rods.

Water is the moderator.

Reply 975

susan23

Original post by sam1am

Ok I did not get 3 ...****.

Reply 976

CharleyChester

Just so everyone knows, there was a mistake in question 3 part c. Our exam invigilator came in half way through our exam and told us :s-smilie:

Reply 977

susan23

Original post by Oh my Ms. Coffey

Water is the moderator.

actually its carbon but I wrote barium for some ****ed up reason!

Reply 978

ViralRiver

I said force was upwards using FLHR. Current went from right to left (or left to right if you use FRHR) - as electron flow is opposite to conventional. Field was sort of coming towards you, so force goes upwards. Hence reading on scale goes up by 0.016N.