Electricity+Magnetism

• What is the topic of the study material?

  Electricity and Magnetism
• What is static electricity?


  • A build-up of electric charge on the surface of objects
  • Caused by the transfer of electrons between insulators
• What do atoms contain?

  Atoms contain positive protons and negative electrons.
• Why do most objects have no net charge?

  Because they have the same number of protons and electrons.
• What happens when electrons are transferred between two objects?

  One object becomes positively charged and the other negatively charged.
• What is static electricity caused by?

  Transferring electrons between objects.
• What do insulators do in terms of electricity?

  Insulators do not allow charged particles to flow through them.
• What happens when charge builds up?

  It can suddenly move, causing static electricity effects.
• What is the relationship between like and opposite charges?

  Like charges repel each other, while opposite charges attract each other.
• How can you demonstrate that an object is charged?

  By placing it near small, neutral scraps of paper.
• What happens to neutral objects when a charged object is brought near?

  The charged object induces a charge in the neutral object.
• What is current in electricity?

  Current is the rate of flow of electrical charge.
• How is current measured?

  Current is measured in amperes (A).
• How is charge measured?

  Charge is measured in coulombs (C).
• What is potential difference?

  Potential difference is the force that pushes charge around a circuit.
• How is potential difference measured?

  Potential difference is measured in volts (V).
• What does resistance do in a circuit?

  Resistance slows down the flow of charge.
• How is resistance measured?

  Resistance is measured in ohms (Ω).
• What is the relationship between charge flow, current, and time?

  • Charge flow (C) = Current (A) x Time (s)
  • Higher current means faster charge flow.
• If a battery charger passes a current of 2 A for 300 seconds, how much charge is transferred?

  600 C
• What are some common circuit symbols you should know?

  • Battery
  • Lamp
  • Resistor
  • Light-Dependent Resistor (LDR)
• What must be ensured when drawing a circuit diagram?

  All wires in the circuit must be straight and the circuit must be closed.
• What is the significance of potential difference in a circuit?

  It is necessary for current to flow through the circuit.
• How do you calculate the time it takes for a current of 2.5 A to transfer a charge of 120 C?

  Time = Charge / Current = $120 \text{ C} / 2.5 \text{ A} =$$48 \text{ s}$
• What is the formula for energy transferred to a component?

  • Energy (J) = Charge (C) x Potential Difference (V)
• What is the formula linking potential difference, current, and resistance?

  Potential difference (V) = Current (A) x Resistance (Ω)
• If a resistor has a potential difference of 60 V and a resistance of 40 Ω, what is the current through the resistor?

  1. 5 A
• If 360 J of energy is transferred through 75 C of charge, what is the potential difference across the resistor?

  $4.8 \text{ V}$
• What are the characteristics of linear circuit elements?

  • Have a constant resistance
  • Resistance does not change with temperature
• What are I-V characteristics?

  • Graphs showing how current changes with potential difference
  • Used to analyze the behavior of circuit components
• How can you investigate I-V characteristics in a circuit?

  1. Set up the circuit with an ammeter and voltmeter.
  2. Vary the resistance to change potential difference.
  3. Record current and potential difference readings.
  4. Plot a graph of current against potential difference.
• What is a thermistor?

  A thermistor is a temperature-dependent resistor.
• How does the resistance of a thermistor change with temperature?

  Resistance decreases as temperature increases.
• What are the applications of thermistors?

  • Used as temperature detectors
  • Used in heating systems
• What is a light-dependent resistor (LDR)?


  An LDR is a resistor whose resistance changes with light intensity.
• How does the resistance of an LDR change with light intensity?

  Resistance decreases as light intensity increases.
• What are the applications of LDRs?

  • Used in automatic lighting systems
  • Used in burglar detectors
• What are the characteristics of series circuits?

  • Current is the same throughout all components
  • Potential difference is shared among components
• What happens to potential difference in a series circuit?

  It is shared among all components.
• What is the relationship between current and potential difference in a series circuit?

  Current is the same everywhere in a series circuit.