Electricity

• What symbol is this?

  Switch

  
• What symbol is this?

  LED

  
• What symbol is this?

  Bulb

  
• What symbol is this?

  Battery

  
• What symbol is this?

  Cell

  
• What symbol is this?

  Ammeter

  
• What symbol is this?

  Voltmeter

  
• What symbol is this?

  Fuse

  
• What symbol is this?

  LDR

  
• What symbol is this?

  Thermistor

  
• What symbol is this?

  Diode

  
• What symbol is this?

  Variable resistor

  
• What symbol is this?

  Resistor

  
• What is electric current?

  flow of electric charge
• What must the circuit include for charge to flow through?

  Potential difference
• What is the equation for charge flow?

  Current (a) x time (s)
• What’s charge flow measured in ?

  Coulombs
• What is the equation for potential difference?

  V= IR

  Potential difference (V) = current (A) x resistance (ohms)
• What‘s the relationship between current and potential difference - resistor?

  Current is directly proportional to potential difference across the resistor
• What’s the relationship between current and potential difference in a filament lamp?

  As resistance of lamp increases the temperature of the lamp increases
• What’s the relationship between current and potential difference - diode?

  Only flows one direction
• What’s the relationship between thermistor and temperature ?

  The resistance in the thermistor decreases, as temperature increases
• What’s the relationship between LDR and light intensity ?

  The resistance of an LDR decreases as light intensity increases
• what’s a series circuit?

  the current is same through all components
• What’s a parallel circuit ?

  Multiple paths for current, the potential difference across each component is the same
• What’s the UK mains electricity supply?

  230 Volts and 50HZ
• What are the two types of electricity supply ?

  AC (alternating current)

  DC (direct current )
• What are the wires in each electrical appliances?

  Brown wire - live wire , provides alternating potential difference from mains supply - 230 V

  Green and yellow stripes - Earth wire , for protection and safety stops the appliance from becoming live doesn't usually carry a current - 0 V

  Blue wire - neutral , completes the circuit current flows through it and live wire , around 0 V
• What’s the equation for energy transferred ?

  energy transferred (J) = power (w) x time (s)
• What’s the equation for Power?

  Power = potential difference x current

  OR

  power = current ^2 x resistance
• What’s the national grid?

  the distributor of electricity , from power stations to consumers
• What are step - up transformers used for?

  To increase potential difference from power station to the transmission cables then step down transformers are used to decrease, to a much lower value, the potential difference for domestic use