b) Resistors

• explain how additional resistors in a series circuit affects the total resistance

• each additional resistor increases the length of the wire

• increases the resistance

• state the formula for the total resistance in a series circuit

• R = R₁ + R₂ + R₃…

  • total resistance of a series circuit (Ω) = resistance of the first resistor (Ω) + resistance of the second resistor (Ω) + resistance of the third resistor (Ω)…

• explain how additional resistors in a parallel circuit affects the total resistance

• each additional resistor increases the number of pathways

• increases the total cross-sectional area of the wires

• decreases the resistance

• state the formula for the total resistance in a parallel circuit

• 1/R = 1/R₁ + 1/R₂ + 1/R₃

  • 1/total resistance of a parallel circuit (Ω) = 1/resistance of the first resistor (Ω) + 1/resistance of the second resistor (Ω) + 1/resistance of the third resistor (Ω)

• state the relationship between the ratio of resistance and the ratio of p.d. between two components in a series circuit

• ratio of R between two components = ratio of V across two components

• 2:1 R between two components = ?

• 2:1 V across two components

• state the relationship between the ratio of resistance and the ratio of current between two branches in a parallel circuit

• ratio of R between two branches = reverse ratio of I between two branches

• 2:1 R between two branches = ?

• 1:2 I between two branches