2.1.3 Current, Resistance & Potential Difference

• potential difference = current x resistance
• resistance = potential difference / current
• current = potential difference/ resistance
• What is potential difference measured in?

  Volts (V).
• What is current measured in?

  Amperes (A).
• What is resistance measured in?

  Ohms.
• What is the symbol for potential difference?

  V.
• What is the symbol for current?

  I.
• What is the symbol for resistance?

  R.
• A 4 ohm resistor in a circuit has a potential difference of 6V across it. What is the current?

  1.5A.
• Is an ammeter placed in series or in parallel?

  In series.
• Is a voltmeter placed in series or in parallel?

  In parallel.
• How does wire length affect resistance?

  Longer wire = greater resistance.
• V = I x R
• What is current dependant on?

  Resistance and potential difference.
• The greater the resistance of a component…?

  The smaller the current for a given potential difference across the component.