Plugs What is a plug?

Back to: PRIMARY SEVEN P7 SCIENCE TOPICAL QUESTIONS AND ANSWERS

Plugs What is a plug?

• A plug is a device that connects an electric appliance to the main source of electricity.
  Qn. Mention the types of plugs.
• Two pin plug
• Three pin plug
  A two pin plug
• A two pin plug consists of two wires.
  i) Neutral wire
  ii) Live wire
  Qn. State the uses of the following wires in a plug.
  a) Neutral wire (Blue or Black)
• The neutral wire takes back current to the source.
  b) Live wire (Red or brown)
• The live wire brings current from the source to the appliance.
  An illustration of a two pin plug.

Qn. Give examples of devices that use a two pin plug.

• DVD players
• Telephones
• Electric fans
• Televisions
• Electric radios
  A three pin plug
• A three pin plug consists of three wires i.e. I. Neutral wire.
  II. Live wire
  III. Earth wire
  Qn. State the importance of the following wires in a three pin plug.
  i) Neutral wire (Black Blue)
• The neutral wire takes current from the appliance back to the source.
  ii) Live wire (Red Brown)
• The live wire brings current from the source to the appliance.
  iv) Earth wire (Yellow or Green)
• The earth wire takes current in the soil incase of two much flow.
• The earth wire prevents electric shock.
  Note
• The cable grip holds the wires together.
  An illustration of a three pin plug

Qn. Give examples of devices that use a three pin plug.

• Electric flat iron
• Electric kettle
• Water heater
• Refrigerator
• Electric cooker
• Hot plates
  Domestic electricity
• The electricity we use in our homes is connected to an electric meter with both the live and neutral wires.
  Qn. State the function of the electric meter.
• The electric meter measures electricity used in a house / building.
  Qn. In which units is electricity measured?
• Kilowatt hours (KWH).