CHAPTER 3

3.1 (a) Describe the microscopic model of current

3.1 (b) Define electric current, I = dQ/dt

3.1 (c) Use electric current, I = dQ/dt, Q = Ne

3.2 (a) State and use Ohm's law

3.2 (b) Define and use resistivity, ρ = RA/l

3.3 (a) Explain the effect of temperature on electrical resistance in metals

3.3 (b) Use resistance, R = R₀ [1 + α(T - T₀)]

3.4 (a) Define emf, ε of a battery and internal resistance, r of a battery

3.4 (b) State the factors that influence internal resistance

3.4 (c) Describe the relationship between emf of a battery and potential difference across the battery terminals

3.4 (d) Use terminal voltage, Vₜ = ε - Ir

3.5 (a) Derive and determine the effective resistance of resistors in series and parallel

3.6 (a) State and describe Kirchhoff's Rules

3.6 (b) Use Kirchhoff's Rules

i. Maximum two close circuit loops

ii. Use scientific calculator to solve the simultaneous equation

3.7 (a) Use power, P = IV, P = I²R, and P = V²/R (known as power loss)

3.7 (b) Use electrical energy, W = IVt

3.8 (a) Explain principle of potential divider

3.8 (b) Use equation of potential divider, V₁ = V (R₁/R₁ + R₂ + ... + R_n)

3.9 (a) Explain principles of the potentiometer and its applications

3.9 (b) Use the related equation for the potentiometer, ε₁/ε₂ = l₁/l₂