3.2.1 Investigating Resistance

• What does resistance measure in a circuit?

  Opposition to electric current
• Longer components have higher resistance
• In Ohm's Law, voltage is measured in volts
• Match the formula with its description:

  $V =$$I \times R$ ↔️ Voltage is the product of current and resistance

  $I =$$V / R$ ↔️ Current is voltage divided by resistance

  $R =$$V / I$ ↔️ Resistance is voltage divided by current
• Steps to set up the experimental circuit for measuring resistance

  1️⃣ Connect the power supply to the switch

  2️⃣ Wire the switch to one end of the resistor

  3️⃣ Connect the other end of the resistor to the ammeter in series

  4️⃣ Connect the ammeter back to the power supply

  5️⃣ Attach the voltmeter in parallel across the resistor

  6️⃣ Turn the power supply ON and flip the switch
• What is the purpose of a resistor in a circuit?

  To oppose current flow
• The power supply should be connected to the switch first when setting up a circuit.
• What law is used to calculate resistance in a circuit?

  Ohm's Law
• Match the factor with its effect on resistance:

  Material ↔️ Varying resistance

  Length ↔️ Higher resistance

  Cross-sectional Area ↔️ Lower resistance
• Match the variable in Ohm's Law with its unit:

  V ↔️ Volts

  I ↔️ Amperes

  R ↔️ Ohms
• Order the formulas derived from Ohm's Law:

  1️⃣ V = I × R

  2️⃣ I = V / R

  3️⃣ R = V / I
• The power supply in a circuit provides the necessary voltage
• Different materials have different resistance values.
• What is the mathematical expression for Ohm's Law?

  $V =$$I \times R$
• Ohm's Law is foundational in understanding basic electrical circuits.
• A voltmeter is connected in parallel across the resistor in the experimental circuit.
• What formula is used to calculate resistance after measuring voltage and current?

  $R =$$V / I$
• A power supply in a circuit provides the necessary voltage
• A voltmeter is attached in parallel across a resistor to measure voltage.
• Longer components have lower resistance.

  False
• The formula for Ohm's Law is V = I × R
• Resistance is measured in ohms
• An ammeter is connected in parallel within a circuit.

  False
• Ensure the switch is in the OFF
• Ohm's Law is expressed as R = V / I
• To calculate resistance using Ohm's Law, you divide voltage by current.
• What is the mathematical expression for Ohm's Law?

  $V =$$I \times R$
• Resistance is measured in the unit of ohms
• A larger cross-sectional area leads to higher resistance.

  False
• What is the formula to calculate current using Ohm's Law?

  $I =$$V / R$
• What is the purpose of an ammeter in the experimental circuit?

  To measure electric current
• Steps to set up an experimental circuit for measuring resistance

  1️⃣ Connect the power supply to the switch

  2️⃣ Wire the switch to one end of the resistor

  3️⃣ Connect the other end of the resistor to the ammeter in series

  4️⃣ Connect the ammeter back to the power supply

  5️⃣ Attach the voltmeter in parallel across the resistor

  6️⃣ Turn the power supply ON and flip the switch
• Resistance is measured in ohms
• What does Ohm's Law state about voltage and current?

  Voltage is proportional to current
• What is the formula to calculate current using Ohm's Law?

  I = V / R
• What device is used to measure electric current in amperes?

  Ammeter
• Match the equipment with its role in the circuit:

  Power Supply ↔️ Provides voltage to the circuit

  Switch ↔️ Controls the flow of electricity

  Resistor ↔️ Component being measured

  Ammeter ↔️ Measures current in amperes
• The voltmeter should be connected in parallel across the resistor.
• Steps to set up the experimental circuit

  1️⃣ Connect the power supply to the switch

  2️⃣ Wire the switch to one end of the resistor

  3️⃣ Connect the other end of the resistor to the ammeter in series

  4️⃣ Connect the ammeter back to the power supply

  5️⃣ Attach the voltmeter in parallel across the resistor

  6️⃣ Turn the power supply on and flip the switch
• Ohm's Law states that voltage is directly proportional to current