CP9 Electricity and Circuits Quiz
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Questions and Answers

What is the defining characteristic of direct current (d.c.)?

  • Change of direction over time
  • Stable voltage levels regardless of load
  • Movement of charge in both directions
  • Movement of charge in one direction only (correct)

    • Which statement correctly describes alternating current (a.c.)?

  • Voltage fluctuates smoothly without interruption
  • The direction of charge movement reverses periodically (correct)
  • It is primarily used in batteries and cells
  • Charge flows evenly in one direction

    • What are the typical voltage and frequency of domestic supply in the UK?

  • 240 V and 60 Hz
  • 230 V and 50 Hz (correct)
  • 120 V and 60 Hz
  • 110 V and 50 Hz

    • How do the live and neutral wires differ in function?

    <p>The live wire provides the current path for appliances, while the neutral wire returns it</p> Signup and view all the answers

    Which statement accurately describes the role of electrical appliances in terms of energy storage?

    <p>Appliances draw energy, impacting stored energy levels in the system</p> Signup and view all the answers

    What is a common voltage level for a typical domestic electrical appliance?

    <p>230 V</p> Signup and view all the answers

    What feature distinguishes alternating current from direct current in practical applications?

    <p>Ease of transmission over long distances</p> Signup and view all the answers

    Which is NOT a characteristic of direct current (d.c.)?

    <p>Changes its magnitude continuously</p> Signup and view all the answers

    During the operation of an a.c. electrical system, what happens to the direction of current?

    <p>It reverses direction periodically</p> Signup and view all the answers

    What is the primary reason for the use of a.c. in domestic supplies?

    <p>It is easier to convert to different voltages</p> Signup and view all the answers

    What would likely occur if an appliance designed for a.c. was connected to a d.c. source?

    <p>The appliance may get damaged</p> Signup and view all the answers

    In terms of energy efficiency, which is a typical behavior of direct current systems?

    <p>Limited application in large-scale distribution</p> Signup and view all the answers

    What factor influences the choice between using d.c. and a.c. in electrical systems?

    <p>The historical development of electrical systems</p> Signup and view all the answers

    Which statement best describes the relationship between electrical appliances' power ratings and energy consumption?

    <p>Increased power ratings lead to higher energy consumption when in use</p> Signup and view all the answers

    What impacts the current in a circuit when resistance changes?

    <p>The current changes in response to the resistance.</p> Signup and view all the answers

    Which equation best defines the relationship between voltage, current, and resistance?

    <p>Voltage = Current × Resistance</p> Signup and view all the answers

    How does electrical energy dissipate when a current operates against resistance?

    <p>As thermal energy in the surroundings.</p> Signup and view all the answers

    What occurs to the power in an electric circuit if both current and voltage increase?

    <p>Power increases proportionally with both current and voltage.</p> Signup and view all the answers

    What effect does increasing the resistance have on the energy transferred in a circuit with a constant potential difference?

    <p>Energy transferred decreases.</p> Signup and view all the answers

    Which materials typically provide higher resistance in electrical circuits?

    <p>Rubber and glass.</p> Signup and view all the answers

    What is the unit of power in electrical terms?

    <p>Watt (W)</p> Signup and view all the answers

    Which factor does not directly influence the total resistance in a circuit?

    <p>Type of circuit arrangement.</p> Signup and view all the answers

    What relationship exists when an electrical current flows through a conductor at a steady temperature?

    <p>Resistance remains constant.</p> Signup and view all the answers

    How can energy be calculated for a circuit with known current, voltage, and time?

    <p>$E = I × V × t$</p> Signup and view all the answers

    In which configuration is current equal in all branches of the circuit?

    <p>Series circuit</p> Signup and view all the answers

    Which of the following devices typically uses a variable resistor?

    <p>Volume controls in audio devices</p> Signup and view all the answers

    Which property allows a conductor to maintain a constant potential difference despite variations in load?

    <p>Internal resistance of the power source</p> Signup and view all the answers

    How can the energy transfer be maximized in a circuit?

    <p>Increasing both current and voltage.</p> Signup and view all the answers

    Study Notes

    CP9 Electricity and Circuits

    • CP9a Electric Circuits:
      • Atoms are composed of protons, neutrons, and electrons.
      • Electrical components have recognized circuit symbols (cells, batteries, switches, voltmeters, ammeters, lamps).
      • Circuit diagrams use standard conventions (positive and negative terminals).
      • Identical lamps in series have different brightness than those in parallel circuits.
      • The brightness of lamps and the effect of different numbers of identical lamps, cells, and switches in series and parallels circuits can be described and explained.

    CP9b Current and Potential Difference

    • Measuring Voltage: Methods of measuring voltage are described.
    • Potential Difference: The term "potential difference" is defined.
    • Measuring Current: Methods of measuring current are described.
    • Electric Current: The conditions necessary to produce an electric current are described (complete circuit and voltage source).
    • Current at Junction: The behavior of current at a junction is described.

    CP9c Current, Charge, and Energy

    • Potential Difference, Charge, and Energy Transfer: The link between voltage, charge flow, and energy transfer are explained. The unit of potential difference (volt) is defined in terms of energy and charge (joule per coulomb).
    • Energy Transfer Equation: The equation for calculating energy transferred, charge flow, and potential difference (E = Q × V) is recalled and used.
    • Current and Electric Charge: Electric current and electrical charge are related.
    • Electric Current in Metals: Electric current in metals is explained in terms of electrons.
    • Charge Flow Equation: The equation for calculating charge, current, and time (Q = I × t) is recalled and used.

    CP9d Resistance

    • Resistance and Current: How changing resistance affects current, using a variable resistor, is explained.
    • Potential Difference = Current × Resistance: Using the equation V = I × R
    • Resistors in Series and Parallel: Why resistance increases in series circuits and decreases in parallel circuits is explained.
    • Calculations in Circuits: Calculate currents, potential differences, and resistances in series circuits described.
    • Circuit Design: The design and construction of circuits for testing and measuring are explained.

    CP9e More About Resistance

    • Filament Lamps: Variation of current with potential difference for filament lamps is explained in relation to resistance.
    • Diodes: Resistance in diodes is described in relation to light intensity.
    • Thermistors: How thermistor resistance changes with temperature change (negative temperature coefficient) is described.
    • LDRs: How light-dependent resistors' resistance varies with light intensity is described.
    • Circuit Construction: Electrical circuits can be used to observe resistance variations in different devices like filament lamps, diodes, thermistors, and LDRs.

    CP9f Transferring Energy

    • Energy Transfer in Resistors: When current flows through a resistor, energy is transferred to heat. This is explained.
    • Dissipation of Electrical Energy: Electrical energy transfers to thermal energy in surroundings when electrical current does work against resistance.
    • Energy Transfer in Circuits: Energy transfer in a circuit is explained as the result of electron collisions and lattice ions.
    • Reducing Energy Transfer: Ways of reducing unwanted energy transfer throughout low resistance wires are explained.
    • Heating Effect of Electricity: Advantages and disadvantages of the heating effect of electric current.
    • Energy Transfer Equation: An equation is provided to calculate energy transferred (E=I×VxT).

    CP9g Power

    • Power Definition: Power is defined as energy transferred per second, in watts.
    • Power Equation: Recall and use the equation P = E/t for power.
    • Power Relationship: How power transfer relates to circuit potential difference and current. Electrical power equations (P = I × V and P = I² × R) are recalled and used.

    CP9h Transferring Energy by Electricity

    • Domestic Devices: How energy transfers in different domestic devices (e.g., motors, heating devices) is described.
    • Direct and Alternating Voltage: Difference between direct and alternating voltage is explained.
    • Direct Current (DC): Direct current in terms of charge movement is described, noting that cells and batteries supply DC.
    • Alternating Current (AC): Alternating current is defined as charge changing direction.
    • UK Domestic Supply: Characteristics of the UK domestic alternating current supply (50 Hz, 230 V) are recalled.
    • Appliance Power Ratings: How appliance power ratings relate to energy use in domestic settings.

    CP9i Electrical Safety

    • Live and Neutral Wires: Difference in function between live and neutral mains wires is explained.
    • Earth Wire: The function of an earth wire is explained, and the importance of fuses or circuit breakers in safety is explained.
    • Wiring Safety: Why switches and fuses should be connected in the live wire of a domestic circuit is explained.
    • Potential Differences: Potential differences between live, neutral, and earth mains wires are recalled.
    • Live and Earth Connection Dangers: The dangers of providing any connection between the live wire and earth are explained.

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    CP9 Electricity and Circuits Past Paper PDF

    Description

    Test your understanding of electric circuits, current, and potential difference with this quiz on CP9 material. Explore concepts such as circuit diagrams, measuring voltage and current, and the behavior of lamps in different circuit configurations. Perfect for students learning about basic electricity principles.

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