SS 2

Revision – Second Term

Physics SS 2 Second Term

📌 Welcome to Your Second Term Revision!

This comprehensive revision covers all the topics from the Second 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 Second Term

Week	Topic	Key Concepts
1	Heat and Temperature (Revision)	Review of First Term topics
2	Electric Current	Definition of current, voltage, resistance; Ohm's Law
3	Resistors in Series and Parallel	Effective resistance; potential difference and current in circuits
4	Cells and Batteries	Primary and secondary cells; EMF and internal resistance
5	Electromagnetism	Magnetic fields; electromagnets; force on a current-carrying conductor
6	Wave Motion	Types of waves (transverse and longitudinal); wave parameters
7	Sound Waves	Production and propagation; echoes; ultrasonics; quality of sound
8	Electromagnetic Waves	Spectrum; properties; applications (radio to gamma rays)
9	Alternating Current	AC generators; transformers; rectification
10	Electronics	Semiconductors; diodes; transistors; simple electronic circuits

Topic 1: Heat and Temperature (Revision) – Summary

🔑 Key Points:

Heat: Energy transferred due to temperature difference.
Temperature: Measure of average kinetic energy of particles.
Scales: K = °C + 273; °F = (9/5)°C + 32
Thermometers: Mercury, alcohol, thermocouple.

Topic 2: Electric Current – Summary

🔑 Key Points:

Current (I): I = Q/t (Amperes)
Voltage (V): V = W/Q (Volts)
Resistance (R): R = V/I (Ohms)
Ohm's Law: V = IR (at constant temperature)
Resistivity: ρ = RA/L

Topic 3: Resistors in Series and Parallel – Summary

🔑 Key Points:

Series: R_T = R₁ + R₂ + R₃ + ...
Parallel: 1/R_T = 1/R₁ + 1/R₂ + 1/R₃ + ...
Voltage: V_T = V₁ + V₂ + ... (series); V same across parallel branches.
Current: I same through series; I_T = I₁ + I₂ + ... (parallel)

Topic 4: Cells and Batteries – Summary

🔑 Key Points:

Primary Cells: Cannot be recharged (e.g., dry cell, Leclanché).
Secondary Cells: Rechargeable (e.g., lead-acid, lithium-ion).
EMF (ε): Total energy per unit charge supplied by the cell.
Internal Resistance (r): Resistance within the cell.
Terminal Voltage: V = ε − Ir

Topic 5: Electromagnetism – Summary

🔑 Key Points:

Magnetic Field: Region around a magnet where force acts.
Electromagnet: Coil of wire with a soft iron core.
Force on a current-carrying conductor: F = BIL sin θ
Right-hand rule: Used to determine direction of force.
Applications: Motors, generators, relays.

Topic 6: Wave Motion – Summary

🔑 Key Points:

Transverse Waves: Particles vibrate perpendicular to wave direction (e.g., light, water).
Longitudinal Waves: Particles vibrate parallel to wave direction (e.g., sound).
Wave Parameters: v = fλ
Frequency (f): Cycles per second (Hz).
Wavelength (λ): Distance between successive crests/troughs.

Topic 7: Sound Waves – Summary

🔑 Key Points:

Production: Vibration of objects.
Propagation: Requires a medium (air, liquid, solid).
Echoes: Reflection of sound waves.
Ultrasonics: Sound waves above 20,000 Hz (used in medical imaging).
Quality of Sound: Determined by harmonics/overtones.

Topic 8: Electromagnetic Waves – Summary

🔑 Key Points:

Spectrum (increasing frequency): Radio → Microwave → Infrared → Visible → UV → X-ray → Gamma
Properties: Transverse, travel at c = 3.0 × 10⁸ m/s in vacuum, no medium needed.
Wave Equation: c = fλ
Applications: Radio (communication), IR (remote controls), UV (sterilisation), X-ray (medical imaging).

Topic 9: Alternating Current – Summary

🔑 Key Points:

AC: Current that reverses direction periodically.
RMS Value: V_rms = V₀/√2; I_rms = I₀/√2
AC Generators: Convert mechanical → electrical (AC).
Transformers: V_s/V_p = N_s/N_p
Rectification: Converts AC to DC (using diodes).
Nigeria mains: 220–240 V, 50 Hz.

Topic 10: Electronics – Summary

🔑 Key Points:

Semiconductors: Materials with conductivity between conductors and insulators.
Diodes: Allow current in one direction (PN junction).
Transistors: Amplify or switch signals (BJT, FET).
Logic Gates: AND, OR, NOT, NAND, NOR (digital electronics).
Applications: Computers, amplifiers, communication systems.

Key Formulas Summary

Topic	Formula	Variables
Ohm's Law	V = IR	V = voltage, I = current, R = resistance
Current	I = Q/t	Q = charge, t = time
Resistance (Series)	R_T = R₁ + R₂ + ...	Sum of resistances
Resistance (Parallel)	1/R_T = 1/R₁ + 1/R₂ + ...	Reciprocal sum
Terminal Voltage	V = ε − Ir	ε = EMF, r = internal resistance
Force on Conductor	F = BIL sin θ	B = magnetic flux density
Wave Equation	v = fλ	v = speed, f = frequency, λ = wavelength
EM Wave	c = fλ	c = 3.0 × 10⁸ m/s
Transformer	V_s/V_p = N_s/N_p	V = voltage, N = turns
RMS	V_rms = V₀/√2	V₀ = peak voltage

Revision Questions

Test your understanding of all Second Term topics:

Section A: Multiple Choice (Choose the correct option)

Ohm's Law states that:
A) V = IR B) I = VR C) R = VI D) V = I/R
The total resistance of two resistors in series is:
A) R₁ + R₂ B) R₁R₂/(R₁+R₂) C) R₁ − R₂ D) R₁/R₂
AC stands for:
A) Alternating Current B) Alternative Current C) Alternate Circuit D) Active Current
Electromagnetic waves travel at:
A) 3.0 × 10⁶ m/s B) 3.0 × 10⁷ m/s C) 3.0 × 10⁸ m/s D) 3.0 × 10⁹ m/s
A diode allows current to flow:
A) In both directions B) In one direction only C) Not at all D) Only in AC circuits

Answers: 1-A, 2-A, 3-A, 4-C, 5-B

Section B: Short Answer Questions

State Ohm's Law and write its mathematical expression.
Distinguish between a primary cell and a secondary cell.
What is an electromagnetic wave? Give two examples.
Differentiate between transverse and longitudinal waves.
What is rectification and why is it important?

Section C: Calculation Questions

A current of 2 A flows through a resistor of 10 Ω. Calculate the voltage across it.
Three resistors of 2 Ω, 3 Ω, and 5 Ω are connected in series. Calculate the total resistance.
Two resistors of 4 Ω and 6 Ω are connected in parallel. Calculate the total resistance.
A transformer has 200 turns on the primary and 50 turns on the secondary. If the primary voltage is 240 V, calculate the secondary voltage.
An electromagnetic wave has a frequency of 6.0 × 10¹⁴ Hz. Calculate its wavelength.

Answers to Section B

1. Ohm's Law: V = IR. At constant temperature, current is proportional to voltage.

2. Primary cells cannot be recharged (e.g., dry cell); secondary cells can be recharged (e.g., lead-acid battery).

3. Electromagnetic waves are transverse waves with oscillating electric and magnetic fields. Examples: radio waves, light.

4. Transverse: particles vibrate perpendicular to wave direction. Longitudinal: particles vibrate parallel to wave direction.

5. Rectification converts AC to DC using diodes. It is important for powering DC devices from AC mains.

Answers to Section C

1. V = IR = 2 × 10 = 20 V

2. R_T = 2 + 3 + 5 = 10 Ω

3. 1/R_T = 1/4 + 1/6 = 5/12 → R_T = 2.4 Ω

4. V_s/V_p = N_s/N_p → V_s = 240 × (50/200) = 60 V

5. λ = c/f = (3.0 × 10⁸)/(6.0 × 10¹⁴) = 5.0 × 10⁻⁷ m

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 circuit diagrams, wave diagrams, and field lines.
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 – SECOND TERM REVISION ║ ╠════════════════════════════════════════════════════════════════════════════╣ ║ ║ ║ WEEK 1: HEAT & TEMPERATURE (Revision) ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • Review of First Term concepts ║ ║ ║ ║ WEEK 2: ELECTRIC CURRENT ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • Ohm's Law: V = IR; I = Q/t ║ ║ ║ ║ WEEK 3: RESISTORS IN SERIES & PARALLEL ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • Series: R_T = R₁ + R₂ + ... ║ ║ • Parallel: 1/R_T = 1/R₁ + 1/R₂ + ... ║ ║ ║ ║ WEEK 4: CELLS & BATTERIES ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • Primary vs Secondary; V = ε − Ir ║ ║ ║ ║ WEEK 5: ELECTROMAGNETISM ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • F = BIL sin θ; Applications: motors, generators ║ ║ ║ ║ WEEK 6: WAVE MOTION ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • v = fλ; Transverse vs Longitudinal ║ ║ ║ ║ WEEK 7: SOUND WAVES ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • Production, propagation, echoes, ultrasonics ║ ║ ║ ║ WEEK 8: ELECTROMAGNETIC WAVES ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • Spectrum: Radio → Microwave → IR → Visible → UV → X-ray → Gamma ║ ║ • c = fλ; Properties: transverse, no medium needed ║ ║ ║ ║ WEEK 9: ALTERNATING CURRENT ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • AC vs DC; V_rms = V₀/√2; Transformers: V_s/V_p = N_s/N_p ║ ║ ║ ║ WEEK 10: ELECTRONICS ║ ║ ───────────────────────────────────────────────────────────────────────── ║ ║ • Semiconductors, diodes, transistors, logic gates ║ ║ ║ ╚════════════════════════════════════════════════════════════════════════════╝

✅ Good luck with your examination!

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