Measuring

• How can we measure the resistance of a component?

  By measuring the current through it and the potential difference across it
• Why is it important to know how to measure resistance?

  Because there is no device that measures resistance directly
• What are the steps to measure resistance using current and potential difference?

  1. Set up the component in series with a cell.
  2. Connect an ammeter in series with the component.
  3. Connect a voltmeter in parallel with the component.
  4. Calculate resistance using the formula: $R =$$\frac{V}{I}$.
  5. Use a variable resistor to change current and potential difference for further measurements.
• What is the best way to set up a circuit to measure resistance?

  A simple circuit consisting of one closed loop
• What role does the ammeter play in measuring resistance?


  The ammeter measures the current flowing through the component
• Where should the ammeter be connected in the circuit?

  In series with the component
• Why should the ammeter have a very low resistance?

  To avoid changing the current when it is connected
• How should the voltmeter be connected to measure potential difference?

  In parallel with the component
• What is the purpose of the voltmeter in the circuit?

  The voltmeter measures the potential difference across the component
• What should the voltmeter's resistance be like?

  It should have a very high resistance
• How do you calculate resistance using the readings from the ammeter and voltmeter?

  Using the formula $R =$$\frac{V}{I}$
• If the ammeter measures a current of 3 A and the voltmeter measures a potential difference of 12 V, what is the resistance?

  The resistance is $4 \, \Omega$
• How does the resistance of a lamp change with current?

  The resistance typically decreases as the current increases
• What is the purpose of using a variable resistor in the circuit?

  To change the current and potential difference
• What happens to the ammeter reading when the variable resistor is adjusted?

  The ammeter reading changes as the current flowing through it changes
• How can you record the results of resistance measurements?

  • Create a table to log current and potential difference readings.
  • Calculate resistance for each pair of readings.
  • Note how resistance changes with varying current.
• What is an IV graph and how is it plotted?

  An IV graph plots current on the Y-axis and potential difference on the X-axis
• What shape do the points on an IV graph for a lamp typically make?

  A smooth curve
• What can be inferred from the shape of an IV graph for different components?

  • Different components have different IV graph shapes.
  • The shape indicates how resistance changes with current.
  • Understanding these shapes is crucial for analyzing component behavior.
• What is the purpose of the Launchpad learning platform mentioned in the material?

  To help students prepare for their exams with interactive resources
• How does the Launchpad learning platform support students?

  By providing quizzes, videos, and AI tutor support