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Official Edexcel Physics Phy4/Phy5 15/06/06 - Before and After

Can some1 tell me what exactly we had to write for the Q on neutral points.
two wires carryin currents and their magnetic feils interacting!!!

this is what I wrote: the magnetic fields from two wires intersect, when the magnetica feild lines are opposite to one another they cancel one another, this is a neutral point where no magnetic field is detected. The two wires must be carrying current in the same direnction.!!!

I wrote that since both the wires carry the same current they both produce circular magnetic fields of the same magnetic flux density. These magnetic fields interact with eachother and overlap, where the flux lines have opposite directions they cancel out- the resultant magnetic field at that point is zero. Such a point is called a neutral point.

hmm i think the opposing direction part is right but not sure about equal B.

Reply 41

King_Julian

Yellowmellow

Can some1 tell me what exactly we had to write for the Q on neutral points.
two wires carryin currents and their magnetic feils interacting!!!

this is what I wrote: the magnetic fields from two wires intersect, when the magnetica feild lines are opposite to one another they cancel one another, this is a neutral point where no magnetic field is detected. The two wires must be carrying current in the same direnction.!!!

I wrote that since both the wires carry the same current they both produce circular magnetic fields of the same magnetic flux density. These magnetic fields interact with eachother and overlap, where the flux lines have opposite directions they cancel out- the resultant magnetic field at that point is zero. Such a point is called a neutral point.

hmm i think the opposing direction part is right but not sure about equal B.

i said everything you said but not the flux density bit, anyway for the fringe question, i measured it by averaging over several fringes.

so i worked out the pattern was 7.8 cm long, which when multiplied by 5mm = 39 mm and divide that over 6 fringe-widths, which gave 6.5mm as fringe width, which i thght was correct as fringe width is the distance from the centre of one minimum to the centre of the adjacent minmum? i might have cobbled it up, and what was the last partt in this question iv forgetten does any one else remember?

Reply 42

Davee1988

PHY5 was actually none too bad, hopefully 35+ out of 40. Any easy PHY5 is always a signal of a hard synoptic though

Reply 43

King_Julian

dont think many ppl did this exam, as not many pple answering any question :frown:

, anyway does any one else remeber the base unit question, was it some thing like kgA-2s-2

Reply 44

forkwise

1

King_Julian

dont think many ppl did this exam, as not many pple answering any question :frown:

, anyway does any one else remeber the base unit question, was it some thing like kgA-2s-2

It was the coulomb law constant:
N m^2 C^-2
kg m s^-2 m^2 A^-2 s^-2
kg m^3 s^-4 A^-2

Reply 45

ArVi

13

forkwise

It was the coulomb law constant:
N m^2 C^-2
kg m s^-2 m^2 A^-2 s^-2
kg m^3 s^-4 A^-2

Yup, that's what I got too

Reply 46

ArVi

13

These are a few of my answers see if they are familiar:

PHY4v = 3.93 ms-1
w1:w2 = 1:1
v1:v2 = 3:2
Energy (leaf question) = 2 * 10^4 J
H = 1.75 * 10^-18
Recession V = 5.8 * 10^7 ms-1

PHY5g (on moon) 2.77 * 10^-3 Nkg-1
h=0.0202m
Current = 2.62A
New balance reading = 84.6g

Reply 47

gfdsa

ArVi

These are a few of my answers see if they are familiar:

PHY5g (on moon) 2.77 * 10^-3 Nkg-1
h=0.0202m
Current = 2.62A
New balance reading = 84.6g

i thought the balance reading doesnt change cuz of newton's third law thing? but anyways i dun really know. the rest of the answers are the same though

Reply 48

forkwise

1

ArVi

PHY5g (on moon) 2.77 * 10^-3 Nkg-1
h=0.0202m
Current = 2.62A
New balance reading = 84.6g

Yes I got those, :smile:

phew, a lot of people had different answers

Reply 49

popop12345

forkwise

Yes I got those, :smile:

phew, a lot of people had different answers

They all seem to a lot of significant figs, i usually do myn to 2???? Why did they give 2 marks for the new reading ? that was the easiest question in the paper?? :rolleyes:

Reply 50

navid

I did pretty good and should get an overall A.

I hope they take the marks up.

Reply 51

ArVi

13

popop12345

They all seem to a lot of significant figs, i usually do myn to 2???? Why did they give 2 marks for the new reading ? that was the easiest question in the paper?? :rolleyes:

I left all my answers to 3sf.

I don't know why the new reading was 2 marks :confused:

Also, are you sure 84.6g is correct?

Reply 52

lesmes

anyone has answers for PHY4 and PHY5? i was aiming for an A but found both papers quite difficult. I had lot of noise from primary children and my teacher made us a "special consideration" form. Does this make final mark go up?

Reply 53

lesmes

ArVi

I left all my answers to 3sf.

I don't know why the new reading was 2 marks :confused:

Also, are you sure 84.6g is correct?

I simply turned wrote the new mass to be negative the one written down.. probably i didn't read the question properly. Do you remember how the question was?

NB/ I wrote -85.6 g I think...

Reply 54

futureaussiecto

13

intensity question-

intensity.sin50.area= power?

im sure it was sin as it sed perpendicular to the line............??

=2.2W

Reply 55

ArVi

13

futureaussiecto

intensity question-

intensity.sin50.area= power?

im sure it was sin as it sed perpendicular to the line............??

=2.2W

Yeah, that's the correct working. It said show that it is ~2W i think :smile:

Reply 56

Popa Dom

2

ArVi

I left all my answers to 3sf.

I don't know why the new reading was 2 marks :confused:

Also, are you sure 84.6g is correct?

When you turned the current on it added an extra 0.4g to the balance, so if you reversed the current, the force on the wire would be reversed(flemmings left hand) , so the force on the magnet would also be reversed (newton 3) so it would be attracted towards the wire. Seeing as the current had the same magnitude, the force would have too, so you subtract 0.4g from the 85g of the magnet.

Reply 57

futureaussiecto

13

Popa Dom

When you turned the current on it added an extra 0.4g to the balance, so if you reversed the current, the force on the wire would be reversed(flemmings left hand) , so the force on the magnet would also be reversed (newton 3) so it would be attracted towards the wire. Seeing as the current had the same magnitude, the force would have too, so you subtract 0.4g from the 85g of the magnet.

whey!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

my c4 might have gone tits-up but my physics hasnt!

Hey, for the accelerated electron,

Path A had a larger radius of curvature (as the attractive force was smaller)

Path B (The anode-cathode pd lowered) meant the speed of the electron was less and the radius of curvature was smaller.

:p:

Reply 58

ArVi

13

futureaussiecto

Path A had a larger radius of curvature (as the attractive force was smaller)

Path B (The anode-cathode pd lowered) meant the speed of the electron was less and the radius of curvature was smaller.

Isn't it the same effect, as the p.d between the two plates decreases in both cases. I drew two slightly different paths for A and B.

Reply 59

futureaussiecto

13

ArVi

Isn't it the same effect, as the p.d between the two plates decreases in both cases. I drew two slightly different paths for A and B.

nah in case A, the pd between the two plates (that control direction of the electron) was decreased, this meant the attractive force on the electron is less and its arc of curvature is greater, so A would be a more gradually arcing curve.

B- was the pd between the anode and cathode, this is what gives the electron is velocity (which is also why they got us to work out the velocity in the Q. before- to jog our memories). If this pd is lowered, the velocity of the electron is less, therefore it travels less distance before being attracted to the plate.

A far as i am aware there were two sets of plates, horizontally (to produce velocity) and vertically (the ones that cause curvature).

Official Edexcel Physics Phy4/Phy5 15/06/06 - Before and After

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