What is a magnetic field?
A force field surrounding a magnet or current-carrying wire
What are magnetic fields lines?
Magnetic field lines emanate from North Pole and end at the South poles
They indicate the direction of force felt by the north pole
Why is the magnetic field not a fundamental field?
Magnetic field/force is a manifestation of the electrostatic field/force
What is the formula for magnetic field strength?
F = BILsin(x)
What is the motor effect?
A current-carrying wire placed at a non-zero angle to magnetic fields will experience a force upon it
What is the rule to remember for a beam of electrons?
Left-hand rule uses conventional current
What is the formula for force using charge and velocity?
F = BQv
What is the formula for circular motion in a uniform magnetic field?
r = mv/BQ
What is a velocity selector?
A velocity selector is a device used to select a charge particle of known velocity to enter mass spectrometer for analysis
What is the formula for the velocity of a particle entering a mass spectrometer?
v = E/B = V/dB
How are molecules separated in a mass spectrometer?
Molecules are separated by their charge per mass
What is the formula for Hall voltage?
VH = BI / ned
‘d’ is the thickness of conductor
How is Hall voltage induced in container?
Magnetic field applied perpendicular to current, electrons deflected toward right-side, leaving left-side semiconductor with fewer electrons
Small voltage develops due to accumulation of electrons
What is the method to determining the uniform magnetic flux density between the poles of a magnet using current-carrying wire and digital balance?
Set up wire between faces of magnet and both wire and magnets on top of balance
Zero the balance
Change supply voltage so current is set
Record reading on mass balance
Repeat for readings at different currents
Measure length of magnets
Graph mean ‘m’ against ‘I
B = gradient x g/L
What do the E-fields and M-fields doing in a cyclotron?
Electrical field accelerates the particle by pulling and repelling it using positive and negative charged plates generating energy
The magnetic force gets a centripetal force maintaining the proton’s motion
What is magnetic flux?
Wb = BA
What is magnetic flux linkage?
(WbN) = BAN
Considers number of coils too
What magnetic flux linkage formula considers the angle?
(WbN) = BANcos(x)
Where ‘x’ is the angle between the plane of the coils and the B-field lines
What is Faraday’s law?
(-)Change (BAN) / Change (Time) = EMF
Changing magnetic field through a coil of wire induces a voltage proportional to the rate of change of the magnetic flux
What is Lenz’s law?
The direction of induced EMF is always such as to oppose the motion that produces it
What is the rule to remember the direction of current and magnetic pole?
In the cross-section of a coil, the curve of the letter ‘N’ or ‘S’ represents the direction of the current
Why must Lenz’s law hold true?
So that the law of conservation of energy is not valid
What is the formula for inducing EMF involving velocity?
EMF = B * v * L
What is the formula for EMF given maximum EMF?
EMF = EMF0 x sin(2pift)
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Chapter 14 - Thermal Physics30
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Chapter 15 - Ideal Gases21
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Chapter 16 - Circular Motion17
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Chapter 17 - Oscillations46
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Chapter 18 - Gravitational Fields44
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Chapter 19 - Stars76
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Chapter 20 - Cosmology (The Big Bang)30
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Chapter 21 - Capacitance28
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Chapter 22 - Electrical Fields13
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Chapter 23 - Magnetic Fields32
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Chapter 24 - Particle Physics24
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Chapter 25 Radioactivity39
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Chapter 26 - Nuclear Physics33
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Chapter 27 - Medical Imaging71
