1.1.2 Potential Difference and Resistance

• What is potential difference measured in?

  Volts (V)
• What is the definition of resistance?

  Opposition to current flow
• Resistance is measured in ohms
• Ohm's Law is expressed mathematically as $V =$$IR$, where V is potential difference, I is current, and R is resistance
• In the water pipe analogy for Ohm's Law, what does water pressure represent?

  Potential difference
• Ohm's Law states that the potential difference across a component is directly proportional to the current and inversely proportional to its resistance
• What are the three main factors affecting the resistance of a conductor?

  Material, length, area
• How does the cross-sectional area of a conductor affect its resistance?

  Inversely proportional
• In a series circuit, the current remains constant throughout the circuit.
• Potential difference is comparable to the difference in water pressure
• What is the unit of resistance?

  Ohms (Ω)
• What does the symbol 'I' represent in Ohm's Law?

  Electric current
• What is the unit of electric current?

  Amperes
• What is the mathematical expression for Ohm's Law?

  $V =$$IR$
• Materials with high resistivity have high resistance
• Match the factor with its effect on resistance:

  Material ↔️ Higher resistivity increases resistance

  Length ↔️ Longer length increases resistance

  Cross-sectional Area ↔️ Larger area decreases resistance
• The total resistance in a series circuit is the sum of individual resistances.
• What is the formula for calculating the total resistance in a parallel circuit with two resistors?

  $\frac{1}{R_{total}} =$$\frac{1}{R_{1}} +$$\frac{1}{R_{2}}$
• Match the circuit type with its properties:

  Series ↔️ Potential difference is divided

  Parallel ↔️ Current is divided
• Ohm's Law states that potential difference is directly proportional to current.
• Match the variable with its symbol and unit:

  Potential Difference ↔️ V, Volts (V)

  Electric Current ↔️ I, Amperes (A)

  Resistance ↔️ R, Ohms (Ω)
• Match the variable with its unit:

  Potential Difference ↔️ Volts

  Electric Current ↔️ Amperes

  Resistance ↔️ Ohms
• The length of a conductor is directly proportional to its resistance.
• In a series circuit, the total potential difference is divided among the components
• In a parallel circuit, the potential difference across each branch is the same as the total potential difference