Q1. Microplastic pollution is a significant environmental issue, with tiny plastic particles accumulating in ecosystems worldwide. These microplastics, common in some cosmetic products, can be electrically charged when ions from solution come to rest on their surface. You have a solution containing spherical microplastic beads each with a radius of 2 micrometres. These particles have a uniform surface charge density of 5 10⁶ Coulombs per square metre.

(a) Determine the total charge on one microplastic particle. How many elementary charges must reside on the surface of the microplastic particle?

(b) If two microplastic particles are 100 micrometres apart, calculate the electrical force between them. Assume the particles have the same magnitude and sign of charge. Are the microplastic beads attracted or repelled by each other? An electric field is applied to cause the microplastic beads to move towards a positively charged electrode. Each particle moves at a consistent velocity of 1.6 mm/s towards the electrode.

(c) Estimate the current produced by a stream of 2400 microplastic beads moving toward the electrode under the influence of an applied electric field. Hint: Consider the time it takes for the particles to travel 1 mm, then the number of particles passing a reference point per second.

(d) Fluids flow and electricity is also often said to "flow". Discuss one similarity and one difference between the flow of fluid and electricity.