Basics of Electricity

• What is required for a simple electrical circuit?

  A conductor and a source of potential difference

  
• How is electric current defined?

  As the rate of flow of electric charge
• In what units is electric current measured?

  Amperes or amps (A)
• What does 1 ampere represent in terms of charge and time?

  1 coulomb flowing in 1 second
• What is the equation for current?

  I = $\frac{\Delta Q}{\Delta t}$
• What does current flow require in a circuit?

  A connection between positive and negative terminals
• What type of charge flows in electric circuits?

  Electrons
• How is conventional current defined?

  As the flow of positive charge

  
• How does the direction of conventional current differ from electron flow?

  Conventional current flows from positive to negative

  
• How is current measured in a circuit?

  Using an ammeter

  
• How must ammeters be connected in a circuit?

  In series with the component being measured
• What is potential difference defined as?

  The electrical work done per unit charge
• In what units is potential difference measured?

  Volts (V)
• What does 1 volt represent in terms of energy and charge?

  1 joule of energy per 1 coulomb of charge
• What is the equation for potential difference?

  V = $\frac{W}{Q}$
• How does a simple cell create potential difference?

  By separating positive and negative charges
• What happens to negatively charged electrons in a cell?

  They are repelled by the negative terminal
• What occurs when a wire connects the two terminals of a cell?

  Electrons flow due to potential difference
• What happens to electrons as they flow through a cell?

  They gain energy
• How much energy does each coulomb gain in a 12 V cell?

  12 joules of energy
• What happens to electrons after leaving a cell?

  They transfer energy to circuit components
• What is the effect of the separation of charges in a battery?

  It creates a potential difference
• How is potential difference measured?

  Using a voltmeter
• How must voltmeters be connected in a circuit?

  In parallel with the component being measured
• When will 8 mA of current pass through a circuit?

  When a charge of 4 C passes in 500 s
• What is resistance defined as?

  The opposition to the flow of electric current
• How is the resistance of a conductor defined?

  As the ratio of potential difference to current
• In what units is resistance measured?

  Ohms (Ω)
• What does a resistance of 1 Ω indicate?

  1 V potential difference produces 1 A current
• How does resistance affect current in a circuit?

  Higher resistance means lower current
• What is the relationship between resistance and current for a given potential difference?

  Lower resistance allows higher current to flow
• What material is often used for wires due to its properties?

  Copper
• Why is copper known as a good conductor?

  Because of its low electrical resistance
• How is the resistance of wires treated in exam questions?

  As zero resistance