Question 1: Explain in your own words what is meant by 'charge flow' in static electricity.

Answer: Charge flow refers to the movement of electric charge, typically electrons, through a conductor, which results in an electric current.

Question 1: What is the primary charge carrier in metals during static electricity experiments?

Answer: Electrons

Question 2: Describe how static electricity can cause a charge to flow between two objects that are initially uncharged.

Answer: When objects are rubbed together, electrons transfer from one object to another, creating a charge imbalance. If the objects are connected, this imbalance causes charge to flow until equilibrium is reached.

Question 1: Calculate the amount of charge (in Coulombs) transferred if a current of 3.0 A flows for 10 seconds.

Answer: Charge Q = I × t = 3.0 A × 10 s = 30 C

Question 2: A static charge of 120 Coulombs is transferred over a period of 60 seconds. What is the average current flowing during this period?

Answer: Current I = Q / t = 120 C / 60 s = 2 A

Question 1: Outline the main variables that should be controlled during an experiment to investigate charge transfer between two materials.

Answer: Variables include the type of materials used, the humidity level, the pressure, the amount of rubbing or friction applied, and the duration of contact.

Question 2: State two safety precautions that should be observed when conducting static electricity experiments.

Answer: Avoid conducting experiments near flammable materials and ensure proper grounding to prevent static shocks.

Question 1: In an experiment, a charged plastic rod transfers 5 microcoulombs (5 × 10⁻⁶ C) of charge over 2 seconds. What was the average current during this transfer?

Answer: I = Q / t = 5 × 10⁻⁶ C / 2 s = 2.5 × 10⁻⁶ A

Question 2: A charge of 200 Coulombs flows through a conductor over a time period of 400 seconds. Interpret what this data suggests about the charge flow compared to typical static electricity experiments.

Answer: The charge flow indicates a steady, relatively high current compared to typical static electricity phenomena, which usually involve smaller charges and brief discharges.

Question 1: Explain how static electricity can lead to charge flow and what factors influence the amount of charge transferred. Include relevant formulas in your explanation. (6 marks)

Answer: Static electricity results from the transfer of electrons between objects due to friction, contact, or induction. When a charge imbalance occurs, electrons move to neutralise the charge difference, causing charge flow. Factors influencing the amount of charge transferred include the type of materials, surface area, and the duration of contact. The relation between charge (Q), current (I), and time (t) is given by Q = I × t, which helps quantify the charge transferred during a static discharge.

Question 1: Describe how understanding charge flow is important in the design of electrostatic precipitators used in pollution control.

Answer: Electrostatic precipitators use static electricity to charge particles in exhaust gases, causing them to be attracted to collection plates. Understanding charge flow allows engineers to optimise the voltage and current to maximise particle collection efficiency while preventing sparks or discharges.

Question 2: Explain how static electricity can be a hazard in industries involving flammable materials and how understanding charge flow can help prevent accidents.

Answer: Static electricity can generate sparks that ignite flammable gases or dust. Understanding charge flow helps industries implement grounding and bonding techniques to prevent charge accumulation and discharge, thereby reducing the risk of sparks and explosions.