Topic 11-Static Electricity

• What is a property of all matter?

  Static electricity
• What types of charges exist?

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

  It forms a neutral body
• What do like charges do?

  They repel each other
• What do opposite charges do?

  They attract each other
• What do insulators do regarding electricity?

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

  Electrons are fixed in place
• What can conduct electricity?

  Conductors
• What allows electrons to flow in conductors?

  Electrons are delocalised
• How can static electricity be generated between two insulators?

  By rubbing them together
• What happens to electrons when two insulators are rubbed together?

  Electrons are transferred between them
• What charge does the object lose electrons acquire?

  A positive charge
• What charge does the object gain electrons acquire?

  A negative charge
• What determines which object loses or gains electrons?

  The materials involved
• What occurs when enough charge builds up between two objects?

  Sparking occurs
• What is the spark that occurs between charged objects?

  Charge jumps through the air
• What causes lightning?

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

  The force of attraction or repulsion between charges
• How does greater charge affect electrostatic force?

  It increases the force
• How does distance affect electrostatic force?

  Closer together increases the force
• What type of force is electrostatic force?

  It is a noncontact force
• What happens when a positively charged balloon is near a wall?

  It attracts electrons in the wall
• What does induction cause in small pieces of paper when a comb is charged?

  It induces the opposite charge
• What is earthing in static electricity?

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

  To remove excess charge and stay neutral
• How are insecticide sprays charged when sprayed from aircraft?

  They are given a charge
• What is the effect of charging insecticide spray droplets?

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

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

  As fuel passes through a hose
• What is the purpose of earthing hoses during fuelling?

  To stop static charge from building up
• What is an electric field?

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

  Away from positive charges, towards negative charges

  
• How does the strength of a charge affect electric field lines?

  Stronger charge has more field lines

  
• What type of electric field do parallel plates create?

  A uniform electric field
• What are the key concepts of static electricity?

  • Positive and negative charges exist
  • Like charges repel, opposite charges attract
  • Insulators do not conduct electricity, conductors do
  • Charging by friction occurs in insulators
  • Sparking occurs when charge builds up
  • Electrostatic forces depend on charge and distance
  • Earthing removes excess charge
• What are the applications and dangers of static electricity?

  Applications:

  • Charged insecticide sprays for even distribution

  
  

  Dangers:

  • Sparks during fuelling can ignite fuel
  • Earthing hoses prevent static charge build-up