SS 2

Revision – Third Term

Physics SS 2 Third Term

📌 Welcome to Your Third Term Revision!

This comprehensive revision covers all the topics from the Third Term. Use this to:

Review key concepts from each topic
Practice with revision questions
Prepare for your end-of-term examination
Identify areas that need more attention

Topics Covered in Third Term

Week	Topic	Key Concepts
2	Magnetism	Magnetic fields, domain theory, Earth's magnetism, angle of dip/declination
3	Electromagnetic Induction	Faraday's Law, Lenz's Law, generators, motors, transformers
4	Wave-Particle Duality	Photoelectric effect, Einstein's equation, de Broglie wavelength
5	Nuclear Physics	Atomic structure, radioactivity, α/β/γ radiation, half-life, fission/fusion
6	Energy Production	Renewable/non-renewable energy, solar, wind, hydro, nuclear, efficiency
7	Satellite Communication	Orbits (GEO, MEO, LEO), GPS, frequency bands, uplink/downlink
8	Optical Instruments	Microscope, telescope, periscope, camera, magnification

Topic 1: Magnetism – Summary

🔑 Key Points:

Magnetic Field: Region around a magnet where force is felt. Lines go from N → S outside, S → N inside.
Domain Theory: Magnetic materials consist of tiny domains. Aligned = magnetised; random = unmagnetised.
Earth's Magnetism: Earth is a giant magnet. Geographic North = Magnetic South. Angle of dip = 0° at equator, 90° at poles.
Materials: Ferromagnetic (Fe, Co, Ni) – strongly attracted; Paramagnetic (Al) – weakly attracted; Diamagnetic (Cu) – weakly repelled.

Topic 2: Electromagnetic Induction – Summary

🔑 Key Points:

Faraday's Law: ε = −N × (ΔΦ/Δt). Induced EMF is proportional to rate of change of flux.
Lenz's Law: Induced current opposes the change that produced it. Explains the negative sign.
Generators: Mechanical → Electrical (AC or DC).
Motors: Electrical → Mechanical (back EMF).
Transformers: V_s/V_p = N_s/N_p = I_p/I_s

Topic 3: Wave-Particle Duality – Summary

🔑 Key Points:

Photoelectric Effect: E_k = hf − φ. Electrons emitted when light frequency exceeds threshold.
Photon Energy: E = hf = hc/λ
de Broglie Wavelength: λ = h/(mv). Matter has wave properties.
Wave Properties: Interference, diffraction, polarization.
Particle Properties: Photoelectric effect, Compton scattering.

Topic 4: Nuclear Physics – Summary

🔑 Key Points:

Atomic Structure: Nucleus (protons + neutrons) + electrons. Atomic notation: ^A_ZX
Radioactivity: α (He nucleus, low penetration), β (electron, medium), γ (EM wave, high penetration).
Half-Life: N = N₀ × (½)^t/T. Time for half of atoms to decay.
Fission: Splits heavy nuclei → energy (nuclear reactors).
Fusion: Combines light nuclei → energy (stars, cleaner).

Topic 5: Energy Production – Summary

🔑 Key Points:

Non-Renewable: Coal, oil, natural gas, nuclear (finite, high emissions).
Renewable: Solar, wind, hydro, geothermal, biomass (inexhaustible, low emissions).
Efficiency: η = (Useful Output / Input) × 100%
Solar: P = A × I × η
Wind: P = ½ρAv³C_p
Hydro: P = ρgQhη

Topic 6: Satellite Communication – Summary

🔑 Key Points:

Orbits: GEO (35,786 km, stationary), MEO (GPS), LEO (ISS, Starlink).
Orbital Velocity: v = √(GM/r)
GPS: 24+ satellites, triangulation, needs ≥4 satellites.
Uplink: Earth → Satellite; Downlink: Satellite → Earth.
Frequency Bands: L (1-2 GHz), S, C, X, Ku (12-18 GHz), Ka (26-40 GHz).

Topic 7: Optical Instruments – Summary

🔑 Key Points:

Microscope: Uses objective + eyepiece (both convex). Total M = M_obj × M_eye.
Telescope: Uses objective (lens/mirror) + eyepiece. M = f_obj / f_eye.
Periscope: Uses two mirrors at 45°. No magnification, changes line of sight.
Camera: Lens focuses light on sensor. Aperture controls light; shutter controls exposure.
Magnification: m = hᵢ/hₒ = v/u

Key Formulas Summary

Topic	Formula	Variables
Electromagnetic Induction	ε = −N(ΔΦ/Δt)	ε = EMF, N = turns, Φ = flux
Transformer	V_s/V_p = N_s/N_p	V = voltage, N = turns
Photoelectric Effect	E_k = hf − φ	E_k = kinetic energy, φ = work function
de Broglie Wavelength	λ = h/(mv)	λ = wavelength, m = mass, v = velocity
Half-Life	N = N₀(½)^t/T	N = remaining, T = half-life
Orbital Velocity	v = √(GM/r)	G = gravitational constant, M = Earth's mass
Magnification	m = hᵢ/hₒ = v/u	h = height, v = image distance, u = object distance

Revision Questions

Test your understanding of all Third Term topics:

Section A: Multiple Choice (Choose the correct option)

The region around a magnet where magnetic force can be felt is called:
A) Magnetic pole B) Magnetic field C) Magnetic domain D) Magnetic flux
According to Faraday's Law, the induced EMF is proportional to:
A) The magnetic field strength B) The rate of change of flux C) The area of the coil D) The current
The photoelectric effect proves that light has:
A) Wave properties only B) Particle properties only C) Both wave and particle properties D) Neither wave nor particle properties
Which type of radiation has the highest penetrating power?
A) Alpha B) Beta C) Gamma D) X-rays
A satellite in geostationary orbit is at approximately:
A) 1,000 km B) 10,000 km C) 35,786 km D) 200,000 km
The total magnification of a compound microscope is the product of:
A) Objective × Eyepiece B) Objective + Eyepiece C) Objective / Eyepiece D) Objective − Eyepiece
Which of the following is a renewable energy source?
A) Coal B) Oil C) Natural Gas D) Solar
The half-life of a radioactive substance is the time for:
A) All atoms to decay B) Half of the atoms to decay C) The activity to double D) The mass to double

Answers: 1-B, 2-B, 3-C, 4-C, 5-C, 6-A, 7-D, 8-B

Section B: Short Answer Questions

State Lenz's Law and explain its significance in electromagnetic induction.
Write Einstein's photoelectric equation and define each term.
Distinguish between nuclear fission and nuclear fusion.
What is the difference between a geostationary satellite and a low Earth orbit satellite?
Draw a labelled diagram of a compound microscope.

Section C: Calculation Questions

A coil has 300 turns. The magnetic flux changes from 0.06 Wb to 0.01 Wb in 0.02 seconds. Calculate the induced EMF.
A metal has a work function of 2.5 eV. Calculate the threshold frequency for this metal. (h = 6.63 × 10⁻³⁴ J·s, 1 eV = 1.6 × 10⁻¹⁹ J)
A radioactive sample has a half-life of 6 days. If the initial mass is 48 g, what mass remains after 18 days?
A telescope has an objective lens with focal length 120 cm and an eyepiece with focal length 4 cm. Calculate its magnification.
Calculate the orbital velocity of a satellite at an altitude of 500 km above the Earth's surface. (R_E = 6.37 × 10⁶ m, M = 5.97 × 10²⁴ kg, G = 6.67 × 10⁻¹¹ N·m²/kg²)

Answers to Section B

1. Lenz's Law: The induced current flows in a direction that opposes the change that produced it. It ensures energy conservation and gives the negative sign in Faraday's Law.

2. E_k = hf − φ. E_k = maximum kinetic energy, hf = photon energy, φ = work function.

3. Fission splits heavy nuclei into lighter ones; fusion combines light nuclei into heavier ones. Fission is used in nuclear reactors; fusion powers the sun.

4. Geostationary (GEO) is at 35,786 km and appears stationary; LEO is below 2,000 km and moves fast around the Earth.

5. (Diagram: objective lens at bottom, eyepiece at top, light path through the tube).

Answers to Section C

1. ε = −N(ΔΦ/Δt) = −300 × ((0.01−0.06)/0.02) = −300 × (−2.5) = 750 V

2. f₀ = φ/h = (2.5 × 1.6 × 10⁻¹⁹) / (6.63 × 10⁻³⁴) = 6.03 × 10¹⁴ Hz

3. n = 18/6 = 3 half-lives. N = 48 × (½)³ = 48 × ⅛ = 6 g

4. M = f_obj / f_eye = 120/4 = 30×

5. r = 6.37×10⁶ + 0.5×10⁶ = 6.87×10⁶ m; v = √(GM/r) = √((6.67×10⁻¹¹ × 5.97×10²⁴) / (6.87×10⁶)) = √(5.80×10⁷) = 7.62 km/s

Examination Preparation Tips

📌 Tips for Success:

Review all formulas – make a formula sheet and memorise them.
Understand key definitions – be able to explain concepts in your own words.
Practice calculations – work through all examples and assignment questions.
Draw diagrams – practice drawing field lines, ray diagrams, and circuit diagrams.
Know your units – be familiar with SI units for all quantities.
Time management – allocate time for each section during the exam.
Read questions carefully – identify what is being asked before answering.

Board Summary

╔════════════════════════════════════════════════════════════════════════════╗ ║ SS2 PHYSICS – THIRD TERM REVISION ║ ╠════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ WEEK 2: MAGNETISM ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • Magnetic field: N→S outside, S→N inside ║ ║ • Domain theory: aligned domains = magnetised ║ ║ • Earth: Geographic N = Magnetic S ║ ║ ║ ║ WEEK 3: ELECTROMAGNETIC INDUCTION ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • Faraday: ε = −N(ΔΦ/Δt) ║ ║ • Lenz: Induced current opposes change ║ ║ • Generator: Mechanical → Electrical ║ ║ • Motor: Electrical → Mechanical ║ ║ ║ ║ WEEK 4: WAVE-PARTICLE DUALITY ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • Photoelectric: E_k = hf − φ ║ ║ • de Broglie: λ = h/(mv) ║ ║ ║ ║ WEEK 5: NUCLEAR PHYSICS ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • α, β, γ radiation ║ ║ • Half-life: N = N₀(½)^(t/T) ║ ║ • Fission vs Fusion ║ ║ ║ ║ WEEK 6: ENERGY PRODUCTION ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • Non-renewable: coal, oil, gas, nuclear ║ ║ • Renewable: solar, wind, hydro ║ ║ • Efficiency: η = (Output/Input) × 100% ║ ║ ║ ║ WEEK 7: SATELLITE COMMUNICATION ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • Orbits: GEO (35,786 km), MEO, LEO ║ ║ • v = √(GM/r) ║ ║ • GPS uses ≥4 satellites, triangulation ║ ║ ║ ║ WEEK 8: OPTICAL INSTRUMENTS ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • Microscope: M = M_obj × M_eye ║ ║ • Telescope: M = f_obj / f_eye ║ ║ • Periscope: mirrors at 45° ║ ║ • Camera: lens, aperture, shutter, sensor ║ ║ ║ ╚════════════════════════════════════════════════════════════════════════════╝

✅ Good luck with your examination!

Remember to stay calm, read all questions carefully, and show your working clearly. You've got this! 💪