[whooshpaddy]

Does anyone have the answers for the end of chapter tests for the blue book?

[nevetstreblig]

(Original post by d_94)
Ughh! God. I freaking hate further mechanics. Yaa. I've been thinking they'd bring up those; also what else do you think would come? What else did your teacher say?

Perhaps worth revising step up/down transformers....they haven't come up yet but ARE in the textbook...it's a fairly simple idea AND an application of magnetic flux thus it has every right to come up....but no doubt we will get it in some hideous Jan-12-esque fashion :P

[d_94]

(Original post by nevetstreblig)
Perhaps worth revising step up/down transformers....they haven't come up yet but ARE in the textbook...it's a fairly simple idea AND an application of magnetic flux thus it has every right to come up....but no doubt we will get it in some hideous Jan-12-esque fashion :P

OMG. I reaalllyyy hate thatt! :/ Is this a resit for you?

[nevetstreblig]

(Original post by d_94)
OMG. I reaalllyyy hate thatt! :/ Is this a resit for you?

Ooooooh yes, got a high C in Jan It was soooo difficult :P

[whooshpaddy]

Transformer question here...

(4 marks)

Assume that the device functions as an ideal transformer. The power line is its primary coil, with one turn; its secondary is the coil round the iron ring, with 1000 turns.

What does ideal mean? (1 mark)

Calculate the value of I(2) if I(1) is 2000A. (2 marks)

[Estelle123]

(Original post by whooshpaddy)
Does anyone have the answers for the end of chapter tests for the blue book?

which one is the blue book? i ahve the edexcel physics for a2 but its black, has a bullet going through an apple at the front?

[Estelle123]

(Original post by whooshpaddy)
Transformer question here...

(4 marks)

Assume that the device functions as an ideal transformer. The power line is its primary coil, with one turn; its secondary is the coil round the iron ring, with 1000 turns.

What does ideal mean? (1 mark)

Calculate the value of I(2) if I(1) is 2000A. (2 marks)

which book is this from?

[Ziviz]

(Original post by whooshpaddy)
Transformer question here...

(4 marks)

Assume that the device functions as an ideal transformer. The power line is its primary coil, with one turn; its secondary is the coil round the iron ring, with 1000 turns.

What does ideal mean? (1 mark)

Calculate the value of I(2) if I(1) is 2000A. (2 marks)

I'm not sure how much detail we need to go into, but my teacher said an ideal transformer was one without ohmic resistance, leakage flux or eddy current losses. Easy to remember but I'm not sure what leakage flux is. But basically it means there's no power loss.

I(secondary)/I(primary) = Number of coils(secondary)/N(primary)

So: Is = (Ip x Ns) / Np

2000 A x 1000/1 = 2x10^6 A or 2000000A


I think the primary number of coils and secondary number of coils are mixed up... 2 million Amps seems an awful lot.. If it was the other way round, then it'd equal 2 amps and that is a lot more easily measured with a standard ammeter.

Just realised the equation is
Vs/Vp = Ns/Np = Ip/Is so it is 2 amps... My mistake! The Amp part is the opposite of the number of coils and Volts part. Take note as it wasn't in my physics text book.

[whooshpaddy]

(Original post by Estelle123)
which one is the blue book? i ahve the edexcel physics for a2 but its black, has a bullet going through an apple at the front?

This one: http://www.amazon.co.uk/Salters-Horn...982778&sr=8-11
There is a red one that goes with this one. Red is concept and Blue is context. I have all answers for red but not blue

(Original post by Estelle123)
which book is this from?

It's from an old edexcel past paper. They are not very different for Unit 4. I think it is Jan 2003, i'm not sure though as my teacher printed them all off for me.

[radenoactive]

What is the differences between these terms? Magnetic flux, flux density, and flux linkage?? This is the most confusing part ever in this unit!!

[whooshpaddy]

(Original post by radenoactive)
What is the differences between these terms? Magnetic flux, flux density, and flux linkage?? This is the most confusing part ever in this unit!!

A magnetic field is a region in which particles with magnetic properties (i.e. a moving charge) experience a force.

Magnetic flux lines show the direction of the movement of the force. Space between the lines of flux indicate field strength.

Magnetic flux density (B) is the magnetic field strength, in other words the force acting per unit current in a wire of unite length, which is perpendicular to the field, and is measured in Tesla. Can be described as the "magnetic flux perpendicular to unit area".

Magnetic flux is the component of the B field passing through that surface. Measured in Webers, φ = BA where A is the area of the surface.

Magnetic flux linkage is the magnetic flux of a coil, where the magnetic flux of each loop is calculated (BA) and then multiplied by the number of loops (N). Φ = NBA and is measured in Webers also.

Does that help at all?

[radenoactive]

(Original post by whooshpaddy)
A magnetic field is a region in which particles with magnetic properties (i.e. a moving charge) experience a force.

Magnetic flux lines show the direction of the movement of the force. Space between the lines of flux indicate field strength.

Magnetic flux density (B) is the magnetic field strength, in other words the force acting per unit current in a wire of unite length, which is perpendicular to the field, and is measured in Tesla. Can be described as the "magnetic flux perpendicular to unit area".

Magnetic flux is the component of the B field passing through that surface. Measured in Webers, φ = BA where A is the area of the surface.

Magnetic flux linkage is the magnetic flux of a coil, where the magnetic flux of each loop is calculated (BA) and then multiplied by the number of loops (N). Φ = NBA and is measured in Webers also.

Does that help at all?

Awesome and simple, as I wanted. Thanks for the great help.

[Estelle123]

(Original post by whooshpaddy)
This one: http://www.amazon.co.uk/Salters-Horn...982778&sr=8-11
There is a red one that goes with this one. Red is concept and Blue is context. I have all answers for red but not blue


It's from an old edexcel past paper. They are not very different for Unit 4. I think it is Jan 2003, i'm not sure though as my teacher printed them all off for me.

ah ok thanks just wanted some extra questions to do and ahh ok yh sorry dont have that one

[M Kh]

(Original post by whooshpaddy)
I'm convinced that we're overdue a 2d momentum question.
This time around, I am going to write the equation in the answers for all the quantifying questions even if it is a long wordy question as looking at the Jan 12 markscheme I lost a lot of marks by not doing this.

I don't understand what you mean by your second sentence. Can you please elaborate?

[M Kh]

Hello all,

I have a request. As the exam approaches, it is becoming really difficult to get over my exam nerves and concentrate on the revision. So I would like to revise with everyone who is interested. I am thinking of deciding a particular time at which everyone who is interested could come online together and we could discuss whatever we need to know for each specification point on the GCE Physics Specification. We did this last year on TSR and it helped a lot - I achieved almost full ums so it really did help a lot. In this way, whoever needs to ask doubts could be replied to immediately. Whoever is interested, please state a suitable time (in GMT) until tonight and we can decide a particular time which suits everyone.

This is for anyone who wants to find out what their local time is in GMT: http://wwp.greenwichmeantime.com/gmt-converter/

These are the Edexcel GCE Physics Unit 4 Specification points that we need to cover:


FURTHER MECHANICS

73 use the expression p = mv

74 investigate and apply the principle of conservation of linear momentum to problems in one dimension

Use of, for example, light gates and air track to investigate momentum.

75 investigate and relate net force to rate of change of momentum in situations where mass is constant (Newton’s second law of motion)

Use of, for example, light gates and air track to investigate change in momentum.

76 derive and use the expression Ek = p2/2m for the kinetic energy of a non-relativistic particle

77 analyse and interpret data to calculate the momentum of (non-relativistic) particles and apply the principle of conservation of linear momentum to problems in one and two dimensions

78 explain and apply the principle of conservation of energy, and determine whether a collision is elastic or inelastic

79 express angular displacement in radians and in degrees, and convert between those units

80 explain the concept of angular velocity, and recognise and use the relationships v = ωr and T = 2π/ω

81 explain that a resultant force (centripetal force) is required to produce and maintain circular motion

82 use the expression for centripetal force F = ma = mv2/r and hence derive and use the expressions for centripetal acceleration a = v2/r and a = rω2.

Investigate the effect of m, v and r of orbit on centripetal force


ELECTRIC AND MAGNETIC FIELDS

83 explain what is meant by an electric field and recognise and use the expression electric field strength E = F/Q

84 draw and interpret diagrams using lines of force to describe radial and uniform electric fields qualitatively

Demonstration of electric lines of force between electrodes

85 use the expression F = kQ1Q2/r2, where k = 1/4πε0 and derive and use the expression E = kQ/r2 for the electric field due to a point charge

Use electronic balance to measure the force between two charges

86 investigate and recall that applying a potential difference to two parallel plates produces a uniform electric field in the central region between them, and recognize and use the expression E = V/d

87 investigate and use the expression C = Q/V Use a Coulometer to measure charge stored

88 recognise and use the expression W = ½ QV for the energy stored by a capacitor, derive the expression from the area under a graph of potential difference against charge stored, and derive and use related expressions, for example, W = ½ CV2

Investigate energy stored by discharging through series/parallel combination of light bulbs

89 investigate and recall that the growth and decay curves for resistor–capacitor circuits are exponential, and know the significance of the time constant RC

90 recognise and use the expression Q = Q0 e-t/RC and derive and use related expressions, for exponential discharge in RC circuits, for example, I = Io e-t/RC

Use of data logger to obtain I-t graph

91 explore and use the terms magnetic flux density B, flux Φ and flux linkage NΦ

92 investigate, recognise and use the expression F = BIl sin θ and apply Fleming’s left hand rule to currents

Electronic balance to measure effect of I and l on force

93 recognise and use the expression F = Bqv sin θ and apply Fleming’s left hand rule to charges

Deflect electron beams with a magnetic field

94 investigate and explain qualitatively the factors affecting the emf induced in a coil when there is relative motion between the coil and a permanent magnet and when there is a change of current in a primary coil linked with it

Use a data logger to plot V against t as a magnet falls through a coil of wire

95 investigate, recognise and use the expression ε = - d(NΦ)/dt and explain how it is a consequence of Faraday’s and Lenz’s laws

PARTICLE PHYSICS

96 use the terms nucleon number (mass number) and proton number (atomic number)

97 describe how large-angle alpha particle scattering gives evidence for a nuclear atom

98 recall that electrons are released in the process of thermionic emission and explain how they can be accelerated by electric and magnetic fields

99 explain the role of electric and magnetic fields in particle accelerators (linac and cyclotron) and detectors (general principles of ionisation and deflection only)

100 recognise and use the expression r = p/BQ for a charged particle in a magnetic field

101 recall and use the fact that charge, energy and momentum are always conserved in interactions between particles and hence interpret records of particle tracks

102 explain why high energies are required to break particles into their constituents and to see fine structure

103 recognise and use the expression ΔE = c2Δm in situations involving the creation and annihilation of matter and antimatter particles

104 use the non-SI units MeV and GeV (energy) and MeV/c2, GeV/c2 (mass) and atomic mass unit u, and convert between these and SI units

105 be aware of relativistic effects and that these need to be taken into account at speeds near that of light (use of relativistic equations not required)

106 recall that in the standard quark-lepton model each particle has a corresponding antiparticle, that baryons (eg neutrons and protons) are made from three quarks, and mesons (eg pions) from a quark and an antiquark, and that the symmetry of the model predicted the top and bottom quark

107 write and interpret equations using standard nuclear notation and standard particle symbols (eg π+, e-)

108 use de Broglie’s wave equation λ = h/p

[whooshpaddy]

(Original post by M Kh)
I don't understand what you mean by your second sentence. Can you please elaborate?

Aaaarrghh, this revision is getting too much and I keep swapping words around, especially if they begin with the same letter.

I meant that in wordy questions (qualifying - not quantifying as I said originally!) I would write the equations involved.

E.g. in the question "Explain why the encoding of the bumps becomes more compressed as the stylus moves towards the centre"

I should have written v = ωr, ω is constant and so the velocity is changing due to the changing radius.

[M Kh]

(Original post by whooshpaddy)
Aaaarrghh, this revision is getting too much and I keep swapping words around, especially if they begin with the same letter.

I meant that in wordy questions (qualifying - not quantifying as I said originally!) I would write the equations involved.

E.g. in the question "Explain why the encoding of the bumps becomes more compressed as the stylus moves towards the centre"

I should have written v = ωr, ω is constant and so the velocity is changing due to the changing radius.

Aaah ohhkay. Never mind, dear. And btw, you are absolutely right, it is very important to include those equations. But how do we know what equations to include? I mean it is very difficult to identify what equations to use and whether to use any. I hope you understand what I am asking.

[M Kh]

Hello all,

I have a request. As the exam approaches, it is becoming really difficult to get over my exam nerves and concentrate on the revision. So I would like to revise with everyone who is interested. I am thinking of deciding a particular time at which everyone who is interested could come online together and we could discuss whatever we need to know for each specification point on the GCE Physics Specification. We did this last year on TSR and it helped a lot - I achieved almost full ums so it really did help a lot. In this way, whoever needs to ask doubts could be replied to immediately. Whoever is interested, please state a suitable time (in GMT) until tonight and we can decide a particular time which suits everyone.

This is for anyone who wants to find out what their local time is in GMT: http://wwp.greenwichmeantime.com/gmt-converter/

These are the Edexcel GCE Physics Unit 4 Specification points that we need to cover:


FURTHER MECHANICS

73 use the expression p = mv

74 investigate and apply the principle of conservation of linear momentum to problems in one dimension

Use of, for example, light gates and air track to investigate momentum.

75 investigate and relate net force to rate of change of momentum in situations where mass is constant (Newton’s second law of motion)

Use of, for example, light gates and air track to investigate change in momentum.

76 derive and use the expression Ek = p2/2m for the kinetic energy of a non-relativistic particle

77 analyse and interpret data to calculate the momentum of (non-relativistic) particles and apply the principle of conservation of linear momentum to problems in one and two dimensions

78 explain and apply the principle of conservation of energy, and determine whether a collision is elastic or inelastic

79 express angular displacement in radians and in degrees, and convert between those units

80 explain the concept of angular velocity, and recognise and use the relationships v = ωr and T = 2π/ω

81 explain that a resultant force (centripetal force) is required to produce and maintain circular motion

82 use the expression for centripetal force F = ma = mv2/r and hence derive and use the expressions for centripetal acceleration a = v2/r and a = rω2.

Investigate the effect of m, v and r of orbit on centripetal force


ELECTRIC AND MAGNETIC FIELDS

83 explain what is meant by an electric field and recognise and use the expression electric field strength E = F/Q

84 draw and interpret diagrams using lines of force to describe radial and uniform electric fields qualitatively

Demonstration of electric lines of force between electrodes

85 use the expression F = kQ1Q2/r2, where k = 1/4πε0 and derive and use the expression E = kQ/r2 for the electric field due to a point charge

Use electronic balance to measure the force between two charges

86 investigate and recall that applying a potential difference to two parallel plates produces a uniform electric field in the central region between them, and recognize and use the expression E = V/d

87 investigate and use the expression C = Q/V Use a Coulometer to measure charge stored

88 recognise and use the expression W = ½ QV for the energy stored by a capacitor, derive the expression from the area under a graph of potential difference against charge stored, and derive and use related expressions, for example, W = ½ CV2

Investigate energy stored by discharging through series/parallel combination of light bulbs

89 investigate and recall that the growth and decay curves for resistor–capacitor circuits are exponential, and know the significance of the time constant RC

90 recognise and use the expression Q = Q0 e-t/RC and derive and use related expressions, for exponential discharge in RC circuits, for example, I = Io e-t/RC

Use of data logger to obtain I-t graph

91 explore and use the terms magnetic flux density B, flux Φ and flux linkage NΦ

92 investigate, recognise and use the expression F = BIl sin θ and apply Fleming’s left hand rule to currents

Electronic balance to measure effect of I and l on force

93 recognise and use the expression F = Bqv sin θ and apply Fleming’s left hand rule to charges

Deflect electron beams with a magnetic field

94 investigate and explain qualitatively the factors affecting the emf induced in a coil when there is relative motion between the coil and a permanent magnet and when there is a change of current in a primary coil linked with it

Use a data logger to plot V against t as a magnet falls through a coil of wire

95 investigate, recognise and use the expression ε = - d(NΦ)/dt and explain how it is a consequence of Faraday’s and Lenz’s laws

PARTICLE PHYSICS

96 use the terms nucleon number (mass number) and proton number (atomic number)

97 describe how large-angle alpha particle scattering gives evidence for a nuclear atom

98 recall that electrons are released in the process of thermionic emission and explain how they can be accelerated by electric and magnetic fields

99 explain the role of electric and magnetic fields in particle accelerators (linac and cyclotron) and detectors (general principles of ionisation and deflection only)

100 recognise and use the expression r = p/BQ for a charged particle in a magnetic field

101 recall and use the fact that charge, energy and momentum are always conserved in interactions between particles and hence interpret records of particle tracks

102 explain why high energies are required to break particles into their constituents and to see fine structure

103 recognise and use the expression ΔE = c2Δm in situations involving the creation and annihilation of matter and antimatter particles

104 use the non-SI units MeV and GeV (energy) and MeV/c2, GeV/c2 (mass) and atomic mass unit u, and convert between these and SI units

105 be aware of relativistic effects and that these need to be taken into account at speeds near that of light (use of relativistic equations not required)

106 recall that in the standard quark-lepton model each particle has a corresponding antiparticle, that baryons (eg neutrons and protons) are made from three quarks, and mesons (eg pions) from a quark and an antiquark, and that the symmetry of the model predicted the top and bottom quark

107 write and interpret equations using standard nuclear notation and standard particle symbols (eg π+, e-)

108 use de Broglie’s wave equation λ = h/p

[M Kh]

Hello all,

I have a request. As the exam approaches, it is becoming really difficult to get over my exam nerves and concentrate on the revision. So I would like to revise with everyone who is interested. I am thinking of deciding a particular time at which everyone who is interested could come online together and we could discuss whatever we need to know for each specification point on the GCE Physics Specification. We did this last year on TSR and it helped a lot - I achieved almost full ums so it really did help a lot. In this way, whoever needs to ask doubts could be replied to immediately. Whoever is interested, please state a suitable time (in GMT) until tonight and we can decide a particular time which suits everyone.

This is for anyone who wants to find out what their local time is in GMT: http://wwp.greenwichmeantime.com/gmt-converter/

[M Kh]

Hello all,

I have a request. As the exam approaches, it is becoming really difficult to get over my exam nerves and concentrate on the revision. So I would like to revise with everyone who is interested. I am thinking of deciding a particular time at which everyone who is interested could come online together and we could discuss whatever we need to know for each specification point on the GCE Physics Specification. We did this last year on TSR and it helped a lot - I achieved almost full ums so it really did help a lot. In this way, whoever needs to ask doubts could be replied to immediately. Whoever is interested, please state a suitable time (in GMT) until tonight and we can decide a particular time which suits everyone.

This is for anyone who wants to find out what their local time is in GMT: http://wwp.greenwichmeantime.com/gmt-converter/

Good Luck revising!