electrical circuits-P4

• What is the relationship between current through a resistor and the potential difference (P.D.) across it?


  Current through a resistor is directly proportional to the P.D. across it.
• What does a voltmeter measure?


  A voltmeter measures the potential difference (P.D.) across a component.
• What is the formula for calculating charge (Q) in terms of current (I) and time (t)?


  Q = I \times t
• How does the resistance of a thermistor change with temperature?


  The resistance of a thermistor decreases as its temperature increases.
• What happens to the total potential difference (P.D.) in a series circuit?


  The total P.D. is shared between the components in a series circuit.
• What is the total potential difference across multiple cells in a circuit?


  The total P.D. across multiple cells is the sum of the P.D. of each cell.
• How do you calculate total resistance in series circuits?


  Total resistance in series is equal to the sum of the resistances of each component.
• What is the total current in a parallel circuit?


  The total current through the whole circuit is the sum of the currents through the separate branches.
• What is the potential difference across components in a parallel circuit?


  The potential difference across all components in a parallel circuit is the same.
• How does total resistance in a parallel circuit compare to the resistance of the least resistant component?


  Total resistance in a parallel circuit is less than the resistance of the resistor with the least resistance.
• What are the key characteristics of parallel circuits?


  • Total current is the sum of currents through separate branches.
  • Potential difference across all components is the same.
  • Total resistance is less than the resistance of the least resistant component.
• What are the key characteristics of series circuits?


  • Total potential difference is shared between components.
  • Total resistance is the sum of the resistances of each component.
  • Current is the same through all components.
• What is the effect of charging by friction on materials?


  • Opposite charges are created on different materials.
  • Charges repel and attract based on their nature (positive or negative).
  • Example: Rubbing a rod with cloth transfers electrons.