electricity

• What is current in an electrical circuit?

  Flow of electrical charge
• What is required for current to flow in a circuit?

  A complete circuit with potential difference
• What is the unit of current?

  Amps
• How does current behave in a single closed loop?

  It has the same value everywhere
• What pushes charge around a circuit?

  Potential difference
• What is the unit of resistance?

  Ohms
• How does resistance affect current flow?

  Greater resistance results in smaller current
• What does the size of the current represent?

  Rate of flow of charge
• What is the formula for charge?

  Charge = current x time
• How is charge measured?

  In coulombs
• What is the formula for potential difference?

  Potential difference = current x resistance
• What happens to charge flow when current increases?

  More charge passes around the circuit
• What characterizes ohmic conductors?

  They have constant resistance
• How does the resistance of some components change?

  Resistance changes with varying current
• What happens to the resistance of a filament lamp when current flows?

  Resistance increases as the component heats up
• How does a diode behave with current flow?

  Resistance stays constant until current changes
• What is an LDR?

  A resistor dependent on light intensity
• How does resistance change in an LDR in bright light?

  Resistance decreases
• What are common applications of LDRs?

  Automatic night lights
• What is a thermistor?

  A temperature-dependent resistor
• How does resistance change in a thermistor as temperature increases?

  Resistance decreases
• What are thermistors used for?

  Useful temperature detectors
• What are the characteristics of sensing circuits?

  • Turn on/increase power to components
  • Depend on environmental conditions
  • Use LDRs and thermistors
• How are components arranged in a series circuit?

  Connected in a line between power supply
• What happens if one component is removed from a series circuit?

  The circuit is completely broken
• How is potential difference distributed in a series circuit?

  Shared between various components
• What is the current behavior in a series circuit?

  The same current flows through all components
• How are components arranged in a parallel circuit?

  Each component is separately connected
• What happens if one component is removed from a parallel circuit?

  It will not affect the circuit
• How is potential difference across components in a parallel circuit?

  It is the same across all components
• How is total current in a parallel circuit calculated?

  Total current equals sum of individual currents
• What are the two types of electricity supplies?

  Alternating current and direct current
• How does alternating current behave?

  It constantly changes direction
• What is the UK mains supply voltage?

  230V
• What type of current do cells and batteries provide?

  Direct current
• How does direct current flow?

  Always in the same direction
• What are the three wires in most cables?

  Neutral, live, and earth wires
• What is the color of the neutral wire?

  Blue
• What is the color of the live wire?

  Brown
• What is the color of the earth wire?

  Green and yellow