Curriculum
Science — Third Preparatory
Science — Third Preparatory
0/8
Science — Third Preparatory 2026/2027
0/4
-
Unit 1 — Chemical Reactions and Their Environmental Impacts
Preview -
Unit 2 — Electricity and Magnetism
Preview
- 1.1 Free electrons and electric current
- 1.2 Electric current intensity
- 1.3 Electric potential difference (voltage)
- 1.4 Electric sources and electromotive force
- 1.5 Connecting electric cells
- 1.6 Electric resistance
- 1.7 Circuit symbols and circuit diagrams
- 1.8 Summary of Lesson 1
- 2.1 How is the current in a conductor determined? Ohm's law
- 2.2 Connecting identical resistors
- 2.3 Electric power and energy
- 2.4 Electrical safety
- 2.5 Summary of Lesson 2
- 3.1 The magnetic effect of electric current
- 3.2 The electromagnet
- 3.3 Magnetic force on a current-carrying wire
- 3.4 The simple electric motor (DC motor)
- 3.5 The electric generator
- 3.6 Summary of Lesson 3
- 📌 Comprehensive Scientific Terminology & Definitions:
- ⚖️ Governing Scientific Laws, Principles & Mathematical Formulas:
- 🔍 In-Depth Explanations, Deductions & Core Concepts:
- 📊 Electrical Measuring Instruments in Prep 3 Science:
- 💡 High-Yield Exam Traps & Key Takeaways:
-
Unit 3 — Variation of Traits in Living Organisms
Preview
-
Unit 4 — Dating Planet Earth
Preview
Unit 1 - Force, Motion, Acceleration and Physical Quantities
0/1
Text lesson
Unit 2 — Electricity and Magnetism
Unit 2 — Electricity and Magnetism
1.2 Electric current intensity
1.2 Electric current intensity
- Imagine watching cars cross a line on a race track.
- In one lap 10 cars cross the line in one minute; in another lap 5 cars cross in one minute.
- The first lap has a higher "rate of crossing".
- The flow of charges in a wire is similar.
- Electric current intensity (I) is the quantity of electric charge that passes through a cross-section of a conductor in one second.
I = Q / t
- where Q is the charge in coulombs (C) and t is the time in seconds (s). The unit of current is the ampere (A), and 1 A = 1 C/s.
- An ammeter measures current. It is connected in series with the part of the circuit whose current is to be measured.
- A charge of 90 C passes through a lamp filament in 3 minutes. Find the current.
- t = 3 × 60 = 180 s. I = Q/t = 90 / 180 = 0.5 A.
Worked example 2
- How much charge flows through a wire carrying 2.5 A for 20 s?
- From I = Q/t, Q = I × t = 2.5 × 20 = 50 C.
- Meaning of a statement. "The current in a wire is 2 amperes" means that a charge of 2 coulombs passes through any cross-section of the wire each second.
Unit 2 — Electricity and Magnetism · 3 / 25