SS 2
Revision β Second Term
Physics
SS 2
Second Term
π 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) β Summary
π Key Points:
- Heat: Energy transferred due to temperature difference.
- Temperature: Measure of average kinetic energy of particles.
- Scales: K = Β°C + 273; Β°F = (9/5)Β°C + 32
- Thermometers: Mercury, alcohol, thermocouple.
Topic 2: Electric Current β Summary
π 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: Ο = RA/L
Topic 3: Resistors in Series and Parallel β Summary
π Key Points:
- Series: RT = Rβ + Rβ + Rβ + ...
- Parallel: 1/RT = 1/Rβ + 1/Rβ + 1/Rβ + ...
- Voltage: VT = Vβ + Vβ + ... (series); V same across parallel branches.
- Current: I same through series; IT = Iβ + Iβ + ... (parallel)
Topic 4: Cells and Batteries β Summary
π Key Points:
- Primary Cells: Cannot be recharged (e.g., dry cell, LeclanchΓ©).
- Secondary Cells: Rechargeable (e.g., lead-acid, lithium-ion).
- EMF (Ξ΅): Total energy per unit charge supplied by the cell.
- Internal Resistance (r): Resistance within the cell.
- Terminal Voltage: V = Ξ΅ β Ir
Topic 5: Electromagnetism β Summary
π 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 ΞΈ
- Right-hand rule: Used to determine direction of force.
- Applications: Motors, generators, relays.
Topic 6: Wave Motion β Summary
π 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 = fΞ»
- Frequency (f): Cycles per second (Hz).
- Wavelength (Ξ»): Distance between successive crests/troughs.
Topic 7: Sound Waves β Summary
π 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 β Summary
π Key Points:
- Spectrum (increasing frequency): Radio β Microwave β Infrared β Visible β UV β X-ray β Gamma
- Properties: Transverse, travel at c = 3.0 Γ 10βΈ m/s in vacuum, no medium needed.
- Wave Equation: c = fΞ»
- Applications: Radio (communication), IR (remote controls), UV (sterilisation), X-ray (medical imaging).
Topic 9: Alternating Current β Summary
π Key Points:
- AC: Current that reverses direction periodically.
- RMS Value: Vrms = Vβ/β2; Irms = Iβ/β2
- AC Generators: Convert mechanical β electrical (AC).
- Transformers: Vs/Vp = Ns/Np
- Rectification: Converts AC to DC (using diodes).
- Nigeria mains: 220β240 V, 50 Hz.
Topic 10: Electronics β Summary
π 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) |
RT = Rβ + Rβ + ... |
Sum of resistances |
| Resistance (Parallel) |
1/RT = 1/Rβ + 1/Rβ + ... |
Reciprocal sum |
| Terminal Voltage |
V = Ξ΅ β Ir |
Ξ΅ = EMF, r = internal resistance |
| Force on Conductor |
F = BIL sin ΞΈ |
B = magnetic flux density |
| Wave Equation |
v = fΞ» |
v = speed, f = frequency, Ξ» = wavelength |
| EM Wave |
c = fΞ» |
c = 3.0 Γ 10βΈ m/s |
| Transformer |
Vs/Vp = Ns/Np |
V = voltage, N = turns |
| RMS |
Vrms = Vβ/β2 |
Vβ = 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) Rβ + Rβ B) RβRβ/(Rβ+Rβ) C) Rβ β Rβ D) Rβ/Rβ
- AC stands for:
A) Alternating Current B) Alternative Current C) Alternate Circuit D) Active Current
- Electromagnetic waves travel at:
A) 3.0 Γ 10βΆ m/s B) 3.0 Γ 10β· m/s C) 3.0 Γ 10βΈ m/s D) 3.0 Γ 10βΉ 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 Ξ©. Calculate the voltage across it.
- Three resistors of 2 Ξ©, 3 Ξ©, and 5 Ξ© are connected in series. Calculate the total resistance.
- Two resistors of 4 Ξ© and 6 Ξ© 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 Γ 10ΒΉβ΄ 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 Γ 10 = 20 V
2. RT = 2 + 3 + 5 = 10 Ξ©
3. 1/RT = 1/4 + 1/6 = 5/12 β RT = 2.4 Ξ©
4. Vs/Vp = Ns/Np β Vs = 240 Γ (50/200) = 60 V
5. Ξ» = c/f = (3.0 Γ 10βΈ)/(6.0 Γ 10ΒΉβ΄) = 5.0 Γ 10β»β· m
Examination Preparation Tips
π Tips for Success:
- Review all formulas β make a formula sheet and memorise them.
- Understand key definitions β be able to explain concepts in your own words.
- Practice calculations β work through all examples and assignment questions.
- Draw diagrams β practice drawing circuit diagrams, wave diagrams, and field lines.
- Know your units β be familiar with SI units for all quantities.
- Time management β allocate time for each section during the exam.
- Read questions carefully β identify what is being asked before answering.