Topic 11: Static Electricity

• What types of charges exist?

  Positive and negative charges
• What happens when a body has equal positive and negative charges?

  They cancel out, forming a neutral body
• What do like charges do?

  Repel each other
• What do opposite charges do?

  Attract each other
• What is the main characteristic of insulators?

  They do not conduct electricity
• Why can't electrons flow in insulators?

  Electrons are fixed in place
• What is a key feature of conductors?

  They can conduct electricity
• How do electrons behave in conductors?

  They flow and are delocalised
• What happens when two insulators are rubbed together?

  They can be charged by friction
• What occurs during the charging of insulators by friction?

  Electrons transfer, creating positive and negative charges
• What happens when two conductors are rubbed together?

  Electrons flow, keeping them neutral
• Why do insulators become charged?

  Electrons cannot flow in them
• What charge forms on an object that loses electrons?

  A positive static charge
• What charge forms on an object that gains electrons?

  A negative static charge
• When does sparking occur?

  When enough charge builds up and objects are close
• What is the nature of a spark?

  Charge jumps through the air to balance
• What causes lightning?

  A large charge difference between clouds and Earth
• What is the electrostatic force?

  The force between charged objects
• How does charge affect electrostatic force?

  Greater charge results in greater force
• How does distance affect electrostatic force?

  Closer objects experience greater force
• What type of force is electrostatic force?

  Non-contact force
• How does a positively charged balloon interact with a wall?

  It attracts electrons in the wall
• What is earthing?

  Allowing electrons to flow to the earth
• What is the purpose of earthing?

  To remove excess charge and stay neutral
• How are insecticide sprays charged?

  They are sprayed from aircraft with a charge
• What is the benefit of charging insecticide spray droplets?

  They repel each other and spread evenly
• What danger can arise from sparks while fueling cars?

  It could ignite and cause an explosion
• How can static charge build up during fueling?

  As fuel passes through a hose
• What is the role of earthing in fueling?

  To stop static charge from causing sparks
• What is an electric field?

  The region where a charge experiences a force
• In which direction do electric fields point?

  Away from positive charges and towards negative charges
• How do electric field lines behave around charges?

  They point at right angles to the surface
• How does the strength of a charge relate to electric field lines?

  Stronger charges have more field lines present