electrical currents

• How does a material become negatively charged?

  By gaining electrons
• How does a material become positively charged?

  By losing electrons
• What will two objects carrying the same type of charge do if brought close to each other?

  Repel each other
• What is an electric field?

  Region of space around charged object
• What happens to the strength of an electric field as you get further from the charged object?

  It decreases
• What is electric current?

  The flow of electrical charge
• What units are charge measured in?

  Coulombs
• What units are current measured in?

  Amperes
• What units are time measured in?

  Seconds
• What is the same at all points when charge flows in a closed loop?

  Current
• What must there be in a closed circuit so that electrical charge can flow?

  Voltage source
• Which two factors does current depend on?

  Voltage and resistance
• What is the unit of voltage?

  Volts
• What is the unit of resistance?

  Ohms
• What happens to the current if the resistance is increased but the potential difference stays the same?

  It decreases
• What is an Ohmic conductor?

  A conductor that obeys Ohm's Law
• What happens to the resistance of a filament lamp as its temperature increases?

  It increases
• What happens to the resistance of a thermistor as its temperature increases?

  It decreases
• What happens to the resistance of a light-dependent resistor when light intensity increases?

  It decreases
• What are the main features of a series circuit?

  • Components are connected end-to-end
  • Current is the same through each component
  • Total resistance is the sum of individual resistances
  • Voltage is divided among the components
• What are the main features of a parallel circuit?


  • Components are connected side by side
  • Voltage is the same across each component
  • Total current is the sum of individual branch currents
  • Total resistance is less than the smallest individual resistance
• In a series circuit, what remains the same through each component?

  Current
• What are the main features of a parallel circuit?

  Voltage is the same across components
• What charge does an object become when it gains electrons?

  Negatively charged
• What charge does an object become when it loses electrons?

  Positively charged
• What happens to like charges?

  They repel each other
• What is an electric field?

  Region around a charged object that experiences force
• What happens to electrostatic force with increasing distance?

  It decreases
• What is current?

  Rate of flow of charge
• What units are used to measure charge, current, and time, respectively?

  Coulombs, Amperes, Seconds
• What provides potential difference in a circuit?

  A voltage source
• What units are used to measure resistance and potential difference respectively?

  Ohms and Volts
• How does the current behave if the resistance is constant?

  The current decreases
• What happens to the current through a conductor if the voltage increases and resistance is kept constant?

  Current is directly proportional to voltage
• What happens to resistance in a conductor if the temperature increases?

  Resistance increases
• What happens to resistance in a conductor if the temperature decreases?

  Resistance decreases
• In a series circuit, what is the current like through each component?

  The same current
• In a series circuit, how is the total potential difference of the power supply distributed?

  Shared between components
• In a series circuit, how is the total resistance calculated?

  Sum of each component's resistance
• In a parallel circuit, what is the voltage across each branch?

  The same