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)

• explain the relationship between the ratio of the resistance between two components and the ratio of the p.d.’s across the two components in a series circuit

• ratio of the resistance between two components = ratio of the p.d.’s across the two components

• a ratio of 2:1 resistance between two components = ?

• a ratio of 2:1 p.d. across the two components

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

• ratio of the resistance within two branches = reverse ratio of the current within the two branches

• a ratio of 2:1 resistance between two branches = ?

• a ratio of 1:2 current within the two branches