A-Level/JC Physics Tuition Singapore/H2 Physics Tuition/JC Physics Tutor

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Hi All A-Level/JC/H2/H1 Physics Students

Topics which are absent in Paper 2

Kinematics
Dynamics
Circular Motion
Gravitational Fields
Electric Fields
Superposition
Alternating Currents
Quantum Physics
Laser and Semiconductors

All the best for your P3

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A-Level Physics Tuition Singapore/H2 Physics Tuition/JC Physics Tutor

2012 A Level MCQ Ans
1A 2A 3D 4D 5D 6C 7C 8B 9B 10B
11A 12B 13A 14D 15C 16A 17D 18C 19B 20B
21A 22B 23D 24D 25A 26B 27A 28C 29A 30A
31D 32A 33B 34D 35C 36A 37C 38C 39D 40C

From A level tutor

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Hi A-level/H2/JC Physics Tuition students

JC2 H2 Physics lesson plan for month Jan and Feb

– Revision on Newtonian Mechanics
– Electromagnetism
– Electromagnetic Induction
– Superposition

Mr Ong SH – A Level/JC/H2 Physics Tutor

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Hi A-level/H2/JC Physics Tuition students

Electromagnetism Definitions

1. Define magnetic flux density.

Magnetic flux density is defined as the force per unit length acting on a conductor carrying a unit current placed perpendicular to the magnetic field.

2. Define the tesla.

The magnetic flux density of a magnetic field is one tesla if the force acting on 1 m length of a conductor carrying 1 A of current placed perpendicular to the field is 1 N.

3.Describe and analyse deflections of beams of charged particles by uniform electric and uniform magnetic fields.

Beams of charged particles entering a perpendicular uniform electric field are deflected in parabolic paths.
Beams of charged particles entering a perpendicular uniform magnetic field are deflected in circular paths.
The direction of the centripetal force is given by Fleming’s left hand rule.

From A level Tutor

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Hi A-level/H2/JC Physics Tuition students

J2 H2 Physics Class will start on 5 Feb 7pm to 9pm

From A Level Physics Tutor

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Hi A-level/H2/JC Physics Tuition students

Electromagnetic Induction

1) Magnetic flux (Φ) through an area A is the product of the area and the component of the flux density B directed normal to the plane of that area [SI unit: weber (Wb)]

2) Magnetic flux linkageis the product of the magnetic flux Φ and the number of turns of the coil N.

3) Faraday’s law: the magnitude of the induced e.m.f. in a coil is proportional to the rate of change of magnetic flux linkagethrough the coil.

Factors affecting the magnitude of the induced e.m.f.
i) the speed of motion of the magnet
ii) the strength of the magnet
iii) the number of turns of the coils

4) Lenz’s law: the direction of the induced current is such that its effect opposes the change producing it. (conservation of energy in that work must be done or energy dissipated against the opposing effects to give rise to induced current i.e. WD = ↑ Electrical Energy due to induced current)

5) For a straight line conductor moving in a uniform magnetic field, the magnitude of the induced e.m.f. ε is given by:
E = BIL

6) Simple applications of EM induction

(i) a.c. generator
Found in typical power stations, a large electromagnet is made to rotate inside fixed coils. The rotating coil causes the flux linkage to change continuously and an e.m.f. is induced in the coils.

(ii) bicycle dynamo
A permanent magnet is made to rotate inside fixed coils. The rotating coil causes the flux linkage to change continuously and induce an e.m.f. in the coils

(iii) transformer
An alternating current in the primary coil produces a varying magnetic field in the core. The secondary coil is also wound round the core, so the flux linking the secondary coil is varying. Hence, a varying e.m.f. is induced across the secondary coil.

From A level/JC Physics Tutors

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Hi All A-Level/JC/H2/H1 Physics Students

Summary: Waves

1) Progressive waves: it consists of a disturbance moving from a source to surrounding places as a result of energy transfer from one point to another.

a) Transverse Waves: a progressive wave in which the direction associated with the motion of disturbance is at right angles to the direction of travel of the wave
Examples: rope waves, electromagnetic waves

b) Longitudinal Waves: a progressive wave in which the direction associated with the motion of disturbance is along the same direction as that of the wave
Example: sound waves, seismic waves

2) Phase and Phase Difference
Two points on a wave are in the same phase when they are precisely in the same state of disturbance at the same time. i.e. same displacement from the equilibrium position, vibrating in the same direction and having the same velocity.

Any 2 points on a wave that are separated by a distance λ (wavelength) or multiples of λ are in phase. Any two crests or any two troughs are in phase, whereas a crest and a trough are in anti-phase or π radians (180 deg) out of phase with each other.

3) Frequency f: number of complete vibrations, or cycles that pass through a given point per unit time. depends on source frequency.

4) Wavelength λ: distance between corresponding points on the wave that are in phase with each other.

5) Velocity of wave v = f x wavelength

For complete summary, please contact Mr Ong @9863 9633

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Hi All A-Level/JC/H2 Physics Students

Summary: Oscillations

1) Terms & Definitions

a) Oscillations: motion in which a body moves about a fixed point, back and forth over the same path. Examples: swinging bob of a simple pendulum, a vibrating guitar string, vibrating tuning fork

b) Periodic motion: motion takes place at equal intervals of time

c) Period T: time taken to complete one oscillation (SI unit: seconds[s] )

d) Frequency f: number of oscillations per unit time (SI unit: hertz [Hz]) f =1/T

e) Angular frequency ω: circular representation of frequency f (SI unit: rad s-1) w = 2pief

f) Equilibrium (neutral) position: position at which no net force acts on the oscillating mass

g) Displacement: distance of the oscillating mass from the equilibrium position at any instant

h) Amplitude: maximum displacement of the oscillating mass from its equilibrium position.

i) Phase: refers to the stage that an oscillating system has reached within the complete cycle of an oscillation, expressed in terms of a fraction of a cycle

j) Phase difference between 2 oscillations: difference in the stages of motion between two oscillations at a specific reference time

For complete summary, please contact Mr Ong @9863 9633

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Hi All A-Level/JC/H2 Physics Students

Current Electricity and Direct Current – Definitions

1. Electric current is the rate of flow of electric charge.

2. Charge is the product of the electric current flowing through a cross section of a circuit and the time of which it flows.

3. One coulomb is the quantity of electric charge that passes through a cross section of a circuit when a steady current of one ampere flows for one second.

4. The potential difference (p.d.) between 2 points in a circuit is defined as the energy converted from electrical to other forms of energy per unit charge passing from one point to the other.

5. One volt is the potential difference between two points in a circuit in which one joule of electrical energy is converted to other forms when one coulomb of charge passes from one point to the other.

6. The electromotive force (e.m.f.) of a source is defined as the energy converted from nonelectrical to electrical per unit charge driven through the source.

7. Resistance of a resistor is defined as the ratio of the potential difference across the resistor to the current flowing through it.
8. One ohm is the electrical resistance of a resistor when a potential difference of one volt across its terminals drives a current of one ampere through it.

For complete summary, please contact Mr Ong @9863 9633

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Alternating Current – Definitions

1. Peak value of an alternating current is defined as the maximum possible value of the alternating current
2. Root mean square current from an AC source is the current which will produce the same heating effect in a resistive load as the steady current from a DC source.
3. Rectification is a process of converting an alternating current to a direct current (flowing in one direction)

Sample Explanation Questions

1. What is a diode?
A diode is an electrical device with two terminals that allows current to flow through it in one direction only.
2. Explain the use of a single diode for the half – wave rectification of an alternating current.

Diode allows current to flow when forward biased, and disallow current to flow when reversed biased.

Current which flows in one direction is called rectified current.
Hence, when an AC supply is connected in a circuit that consists of a single diode and a resistor in series, only the rectified current can flow through the resistor.

For complete summary, please contact Mr Ong @9863 9633

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J1 – Teaching forces and dynamics part 3

J2 – Practice AC exam papers questions and start teaching quantum physics

From A Level Physics Tutors

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Quantum Physics – Definitions

1. Photon is a quantum of electromagnetic radiation.

2. Photoelectric effect is a phenomenon where electrons are liberated from the surface of a metal when the metallic surface is irradiated with electromagnetic radiation of high enough frequency.

3. Threshold frequency of a metal is the frequency of the incident electromagnetic radiation below which no electrons can be liberated from the metal surface.

4. Work function enrgy of a metal is the minimum energy required to liberate an electron from the surface of the metal.

5. A potential barrier is a region within which the potential energy of the particle is much higher than that immediately outside it.

6. Quantum tunneling is a phenomenon where a particle can appear outside a potential barrier, even though the total energy of the particle is lower than the barrier height.

A Level Physics Tutors

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Exam based questions – Quantum Physics

1. Show an understanding that photoelectric effect provides evidence for a particulate nature of electromagnetic radiation.

Electromagnetic radiation is considered as a stream of photons.
Photoelectric effect provides the evidence for the particulate nature of electromagnetic radiation.

2. What evidences show that light has wave and particulate natures?

Diffraction and interference of light is the evidence for its wave nature.
Photoelectric effect is the evidence of its particulate nature.

3. What are the 4 results of the photoelectric effect experiments?

Result 1: Current is proportional to intensity. This result can be explained using wave nature and particulate nature of light.

Result 2: For every material of cathode irradiated, there is a limiting frequency fo or threshold frequency, below which no electrons would be emitted from the cathode regardless of the light intensity.
This result can be explained using particulate nature of light only.

Result 3: The maximum kinetic energy of emitted photoelectrons depends only on the frequency of the incident radiation, and not its intensity.
This result can be explained using particulate nature of light only.

Result 4: The emission of photoelectrons starts with no observable time lag, even for very low intensity of incident radiation.
This result can be explained using particulate nature of light only.

4. Explain photoelectric phenomena in terms of photon energy and work function energy.

Work function energy is the minimum energy required to remove an electron from the surface of the metal.

If the photon energy is less than the work function energy of the cathode, no photoelectron will be emitted. Hence, to emit photoelectrons, photon energy must be equal or greater than the work function energy of the cathode.

For more exam based questions, please contact Mr Ong @9863 9633

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Exam based questions – Quantum Physics

5. Describe and interpret qualitatively the evidence provided by electron diffraction for the wave nature of particles.

When a beam of electrons passed through a thin film of crystal (e.g. graphite),the dispersion pattern of the emergent electrons produced on a screen (coated fluorescent)is observed to be similar to the diffraction pattern produced by a beam of X-ray.

This phenomenon provides evidence for the wave nature of particles like electrons.

6. Explain how spectral lines show discrete energy levels in an atom.
An emission spectrum consists of a set of discrete wavelengths.

A photon is emitted from an isolated atom when one of its electrons transits from a higher to a lower energy level.
Energy of the photon is equal to the energy difference between the two levels involved in the transition.

7. Distinguish between emission and absorption line spectra.

An emission line spectrum of an element consists of colored lines on dark background while an absorption spectrum consists of dark lines on colored background, at the same discrete wavelength positions for the same element.

For emission spectra, electrons transit from higher energy level to lower energy level.For absorption spectra, electrons transit from lower energy level to higher energy level.

9. Explain the origins of the features of a typical X – ray spectrum using quantum theory.

It is produced in an X-ray tube, where fast electrons strike a metallic target (e.g. tungsten).

Two distinct features of an X-ray spectrum:
Spikes (Ka and Kb)

– due to characteristic radiation of the target metal in which electrons transit from very high to low energy level.

For more exam based questions, please contact Mr Ong @9863 9633

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Hi A-level/H2/JC Physics Tuition students

Definitions -Errors & Uncertainties

1. Systematic error
A systematic error is one that occurs consistently more or consistently less than the actual reading.

2. Random error
A random error is one that gives a scatter of readings about a mean value

3. Accuracy
The closeness of a reading on an instrument to the true value of the quantity being measured.
If an experiment has small systematic errors, it is said to have high accuracy.

4. Precision
A term used to describe the level of uncertainty in an instrument‟s scale.
If an experiment has small random errors, it is said to have high precision.

5. Uncertainty
The range of values on both sides of a measurement in which the actual value of the measurement is expected to lie.

6. Scalar quantity
Scalar quantity is a physical quantity that can be represented by a magnitude only. It does not have a direction.

7. Vector quantity
Vector quantity is a physical quantity that can be represented by a magnitude and a direction.

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