A stainless steel medical trolley is pushed along a synthetic polymer floor in a hospital corridor. Due to the contact between the rubber wheels and the floor, the trolley gains a net static electric charge.
Explain how the trolley gains an electric charge.
When a nurse touches the metal frame of the trolley, there is a visible spark and the nurse receives a mild electric shock. The spark lasts for 80 ms80\text{ ms}80 ms, during which 0.0028 C0.0028\text{ C}0.0028 C of charge is transferred.
State the equation linking charge, current, and time.
Calculate the average current in the spark. Give the unit.
The nurse is wearing earthed anti-static shoes. Explain why the nurse still receives a shock when touching the charged trolley.