Physics P3

• What are the two types of charge?

  Positive and negative
• What happens when a body has equal amounts of positive and negative charge?

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

  Like charges repel each other
• What do opposite charges do to each other?

  Opposite charges attract each other
• What is the characteristic of insulators regarding charge?

  Insulators don’t conduct charge
• Why can conductors conduct charge?

  Because their charged particles are delocalised and can flow
• What occurs when two insulators are rubbed together?

  Electrons are transferred from one to the other
• What charge does the object losing electrons acquire?

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

  A negative charge
• What happens to conductors when rubbed together?

  Electrons flow in and out, remaining neutral
• What is sparking?

  When charge jumps through the air to balance out charges
• What is electrostatic force?

  A force that can be attractive or repulsive between charged objects
• What factors increase the electrostatic force between charged objects?

  Greater charge and smaller separations
• What type of force is electrostatic force?

  It is a non-contact force
• How do charged objects affect small neutral objects nearby?

  They induce a charge inside them, causing attraction
• What happens to a stream of water near a charged object?

  The stream bends towards the charged object
• How does the strength of a charge relate to electric field lines?

  Stronger charges have more field lines
• What is required for a current to flow?

  A closed circuit and a source of potential difference
• What does potential difference (p.d.) measure?

  The energy transferred per unit charge
• How is potential difference measured?

  Using a voltmeter placed in parallel across a component
• What does current represent?

  The rate of flow of charge (electrons)
• How is current measured?

  Using an ammeter placed in series
• What is a series circuit?

  A closed circuit where the current follows a single path
• What is a parallel circuit?

  A branched circuit where the current splits into multiple paths
• What is the relationship between current and voltage in a constant resistance?

  The graph of current against voltage is linear
• What happens to resistance as current increases?

  Resistance increases as electrons collide with atoms
• How does temperature affect resistance in normal wires?

  Resistance increases with temperature due to increased atomic vibrations
• How do thermistors behave with temperature changes?

  Resistance is lower at higher temperatures
• How does the length of a wire affect resistance?

  Greater length results in more resistance
• How does cross-sectional area affect resistance?

  Thinner wires give greater resistance
• What happens to resistance in light-dependent resistors (LDRs) with increased light intensity?

  Resistance decreases with greater light intensity
• What is the function of diodes in circuits?

  Diodes allow current to flow freely in one direction
• What is the formula for calculating power in a circuit?

  Power = Current × Voltage
• What is the formula for calculating energy in terms of charge and potential difference?

  Energy = Charge × Potential Difference
• What is the total resistance in a series circuit?

  The total resistance is the sum of the resistance in each component
• What is the total resistance in a parallel circuit?

  The total resistance is less than the branch with the smallest resistance
• What is the relationship between power and time in terms of energy?

  Energy = Power × Time
• What is the relationship between current, voltage, and resistance in a circuit?

  Voltage = Current × Resistance
• What are the characteristics of series and parallel circuits?

  Series Circuit:

  • Current is the same everywhere
  • Components connected end to end
  • Total resistance is the sum of individual resistances

  
  

  Parallel Circuit:

  • Current splits into multiple paths
  • Voltage is the same across each branch
  • Total resistance is less than the smallest branch resistance
• What factors affect resistance in a circuit?

  Factors affecting resistance:

  • Current: Increases with higher current
  • Temperature: Increases with temperature for normal wires, decreases for thermistors
  • Length: Greater length increases resistance
  • Cross-sectional area: Thinner wires increase resistance
  • Light: LDRs have lower resistance with higher light intensity
  • Voltage: Diodes allow current in one direction, high resistance in the opposite