electric circuits

• What do electrical circuit symbols represent?

  They represent different components found in an electrical circuit.
• What are some common electrical circuit components?

  • Switch
  • Lamp
  • Fixed resistor
  • Variable resistor
  • Thermistor
  • Light-dependent resistor (LDR)
  • Semiconductor diode
  • LED
  • Cell
  • Battery
  • Fuse
• What is the function of a switch in an electrical circuit?

  A switch is used to turn a circuit on (closed) and off (open).
• How does a lamp produce light?

  An electrical current heats the filament in a bulb to produce light.
• How does a variable resistor work?

  Moving the slider changes the resistance in a variable resistor.
• What is the purpose of a fixed resistor?

  A fixed resistor restricts or limits the flow of electrical current.
• What happens to the resistance of a thermistor as temperature increases?

  The resistance of a thermistor decreases as temperature increases.
• What is the function of a light-dependent resistor (LDR)?

  The resistance of an LDR depends on light intensity.
• What are the two types of electrical current?

  The two types of electrical current are direct current and alternating current.
• What is a semiconductor diode used for?

  A semiconductor diode allows current to flow in one direction only.
• How does direct current differ from alternating current?

  In direct current, the flow of electrons is consistently in one direction.
• What is charge in the context of electricity?

  Charge is a property of a body that experiences a force in an electric field.
• How is charge measured?

  Charge is measured in coulombs (C).
• How many electrons are in one coulomb of charge?

  One coulomb of charge is equivalent to 6,250,000,000,000,000,000 electrons.
• What is electrical current?

  Electrical current is the rate of flow of electric charge.
• How can the amount of charge passing a point in a circuit be calculated?

  Charge can be calculated using the equation: charge = current × time.
• How is current measured in a circuit?

  Current is measured using an ammeter.
• What is the unit of current?

  Current is measured in amps (A).
• How must an ammeter be connected to measure current through a component?

  An ammeter must be placed in series with that component.
• What does potential difference refer to?

  Potential difference refers to the difference in energy from one side of a component to the other.
• What is the unit of potential difference?

  Potential difference is measured in volts (V).
• How is potential difference calculated?

  Potential difference can be calculated using the equation: potential difference = current × resistance.
• What is the relationship between energy, voltage, and charge?

  When a charge moves through a potential difference, electrical work is done and energy is transferred.
• How is potential difference calculated when charge moves?

  Potential difference can be calculated using the equation: potential difference = energy / charge.
• What is Ohm's Law?

  Ohm's Law states that the potential difference is directly proportional to the current for a fixed resistor.
• What happens to the resistance of a filament bulb as the potential difference increases?

  The resistance of a filament bulb increases as the potential difference increases.
• What is the effect of temperature on the resistance of a filament bulb?

  As the temperature of the filament increases, the resistance also increases.
• What are the steps to investigate the factors that affect resistance in a wire?

  1. Record the length of the wire accurately.
  2. Measure and observe the potential difference and current.
  3. Use appropriate apparatus to measure current and potential difference.
  4. Calculate resistance using \( R = \frac{V}{I} \).
  5. Plot a graph of resistance against length.
• What are the results of the resistance experiment with varying wire lengths?

  • Resistance increases with length.
  • Direct positive correlation shown in the graph.
• What are the hazards and control measures in resistance experiments?

  Hazards:

  • Heating of the resistance wire

  Control Measures:

  • Do not touch the wire while connected.
  • Allow the wire to cool before handling.
• What is the evaluation of the current-voltage relationship for a fixed resistor?

  • Potential difference is directly proportional to current.
  • Doubling energy results in double the current.
• What is the aim of the current-voltage graph experiment?

  To investigate the relationship between current and potential difference for:

  • Resistor
  • Bulb
  • Diode
• What is the evaluation of the current-voltage relationship for a filament bulb?

  • Current does not increase as fast as potential difference.
  • Resistance increases with temperature, making it harder for current to flow.
• What is the purpose of a protective resistor in a diode circuit?

  A protective resistor limits the current flowing through the diode.
• What is the range of values for a suitable protective resistor in a diode circuit?

  A suitable protective resistor should be between 100 Ω and 500 Ω.
• What is the potential difference at a current of 1.38 A?

  1. 5 V
• What is the potential difference at a current of 1.41 A?

  1. 0 V
• What is the potential difference at a current of 1.44 A?

  1. 5 V
• What is the potential difference at a current of 1.48 A?

  1. 5 V
• What is the potential difference at a current of 1.46 A?

  1. 0 V