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AQA Physics B Unit 5 - How did you do? watch

1. (Original post by Wings)
approx. 2.5m it has to be half the wavelength of original wave since it starts 180 degrees outa phase
I got 2.3.

Worked out Lambda by using v = fLambda

Then divided it by 2, is that what you did?
2. yeh thats correct
3. For the question where it had the electron as a standing wave, when it told you to calculate the Potential energy, did you use the formula? I thought you needed to use the formula but they didnt give you the charges of an electron/proton so I just went back and found the charge of an electron...

Also, for the graph question, did you find the numbers of squares x value of one square, times the mass of the satellite?
4. Btw wen u said it will not exceed 1.5% you were rite.. so relax.

To work out intensity u had to say

Intensity= Activity in one sec X energy per molecule

The activity is found by saying A=N lambda (u know lambda since u had to work it out)
5. (Original post by Wings)
Btw wen u said it will not exceed 1.5% you were rite.. so relax.

To work out intensity u had to say

Intensity= Activity in one sec X energy per molecule

The activity is found by saying A=N lambda (u know lambda since u had to work it out)
Did you get 1.5% as well?
6. Yeh i got 1.5%

The charge question is the only one i cudnt do. didnt give me charge ??

And yes u just had to times area by mass of satellite. However, i missed the estimate bit and worked it out with the formulae. The mass of sun cud easily be worked out by taking a point on the graph and saying g= Gm/r^2 where m is mass of earth.

Eith way is correct.. I just did it the much longer way..o well
7. (Original post by Wings)
Yeh i got 1.5%

The charge question is the only one i cudnt do. didnt give me charge ??

And yes u just had to times area by mass of satellite. However, i missed the estimate bit and worked it out with the formulae. The mass of sun cud easily be worked out by taking a point on the graph and saying g= Gm/r^2 where m is mass of earth.

Eith way is correct.. I just did it the much longer way..o well
What charge question are we talking about here?
8. work out potential energy of electron.. some reason that got me???

Pe= Qq/ (4 pi E r)

Where the heck was Q or q (ie charges of particles.. or were i to simply assume they were +1 and -1 ???)
9. (Original post by Wings)
work out potential energy of electron.. some reason that got me???

Pe= Qq/ (4 pi E r)

Where the heck was Q or q (ie charges of particles.. or were i to simply assume they were +1 and -1 ???)
Yeh thats the question Im on about

I went back, found the charge of an electron(1.6x10^-19) and seen as the chrage on a proton is equal but opposite, its just (1.6x10^-19)^2

Thats how I did it, but like you say, they didnt give us charges so maybe they were expecting a different method?
10. Well its not TOO many marks anyway so shudnt matter too much.. especially if around 58/100 wud be an A.

So relax.. at least all the physics is OVER!!!

lol

What uni u hoping to goto m8?
11. (Original post by Wings)
Well its not TOO many marks anyway so shudnt matter too much.. especially if around 58/100 wud be an A.

So relax.. at least all the physics is OVER!!!

lol

What uni u hoping to goto m8?
York, you?
12. Hopefully UCL : )

What u studying?
13. (Original post by Wings)
Hopefully UCL : )

What u studying?
Physics
14. Also, I thought it was quite strange having 2 questions saying stuff like:

'Show that the kinetic energy of the electron can be represented by this equation 3 marks for rearranging equations..I have to add I though they were pretty tricky equations as well :|
15. ive did so terrible, need an A but its looking very unlikely! Did ne 1 get 1m fot the length for da plate, plz say yes cuz its bout da only one i cud do
16. (Original post by Marie123)
ive did so terrible, need an A but its looking very unlikely! Did ne 1 get 1m fot the length for da plate, plz say yes cuz its bout da only one i cud do
Yes I got 1m, I thought I did it wrong though.

I did Ft = mv

found t, multiplied by 0.80
17. Are you talking bout how the long the plate has to be in order to catch the dust particle??
18. (Original post by imasillynarb)
York, you?
what's your offer and what are you expecting?
19. (Original post by Wings)
Are you talking bout how the long the plate has to be in order to catch the dust particle??
Yeh
20. (Original post by elpaw)
what's your offer and what are you expecting?
BBB, god knows what Im gonna get though. I was hoping for AAB, but it seems increasingly unlikely, and depending on how chemistry goes tomorrow Itll probably be BBC Why?

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