Electricity +Magnetism

• What are the two types of electric charge?

  Positive and negative
• What happens when two charged objects are brought close together?

  Like charges repel, unlike charges attract
• In what units is electric charge measured?

  Coulombs
• What are atoms made of?

  Tiny particles called atoms
• What is the charge of protons and neutrons?

  Protons are positive, neutrons have no charge
• What is a neutral atom?

  An atom with equal numbers of electrons and protons
• What is a positive ion?

  An atom that has lost electrons
• What is a negative ion?

  An atom that has gained electrons
• What is an electric field?

  Region around a charge where force is experienced
• How do electric field lines behave?

  They point away from positive charges towards negative charges
• What indicates the strength of an electric field?

  Field lines are close together for stronger fields
• What happens to electric field lines in a uniform electric field?

  They are parallel and evenly spaced
• How are charges distributed on a conducting sphere?

  Evenly distributed on the surface
• What is a conductor?

  Material that allows charge to flow easily
• Why do metals conduct electricity well?

  They have free moving electrons
• What is an insulator?

  Material that does not allow charge flow easily
• How can an insulator be charged by friction?

  Electrons transfer from one object to another
• What happens when a negatively charged rod is brought near a neutral metal sphere?

  Negative charges in the metal are repelled
• What is the effect of connecting an earth wire to a charged metal sphere?

  Negative charges can leave the sphere
• What happens when a positively charged rod is brought near a neutral metal sphere?

  Negative charges in the metal are attracted
• What is electrostatic phenomena?

  Effects caused by static electric charges
• How does a charged ruler attract uncharged paper?

  Electrons in paper are attracted to the ruler
• Why does a negatively charged balloon attract water?

  It attracts positive charges in the water
• What causes lightning during a thunderstorm?

  Attractive force between clouds and ground charges
• What is electric current?

  Flow of charge per second
• What is the equation for electric current?

  I = Q / T
• What is the unit of electric current?

  Ampere
• In what direction does conventional current flow?

  From positive to negative terminal
• What happens when a battery is connected to a conductor?

  Electrons flow from negative to positive terminal
• What is the role of a voltmeter?

  Measures voltage across components
• What is the equation for potential difference?

  V = W / Q
• What is the unit of potential difference?

  Volt
• What happens when cells are connected in series?

  Total EMF is the sum of individual EMFs
• What happens when cells are connected in parallel?

  Total EMF remains the same as one cell
• What is resistance?

  Ratio of potential difference to current
• What is the equation for resistance?

  R = V / I
• What is the unit of resistance?

  Ohm
• What is a fixed resistor?

  Component that controls current in a circuit
• What is a variable resistor?

  Component that can change resistance in a circuit
• How does temperature affect resistance in metallic conductors?

  Resistance increases as temperature increases