Question

A group of students are doing an electrostatic experiment. One touches an electroscope with her finger, and a second student then brings a charged plexiglass rod near the electroscope but does not touch it. The first student removes her finger from the electroscope before the second student removes the plexiglass. Meanwhile a third student touches a different electroscope with a charged PVC pipe. Are both electroscopes charged? If so, are they the same charge or different charges? Explain your reasoning. Feel free to include any drawings or diagrams.

Answer 1

Answer:

a) If both are charged

b) the first team has a load and the second half of it

c) The first team has a charge contrary to the rod, it is charged by induction and the second team has a charge equal to the rod, it is charged by contact

Explanation:

For this exercise let's analyze the charge on each electroscope separately

electroscope 1

Suppose the student with her finger on the device is grounded,

When bringing the rod closer to the electroscope a charge is indexed, on the side of the rod on the opposite side there is the same charge but with the opposite sign, as the student is grounded, this charge passes to the ground, this side remains neutral.

When removing the finger, loads can no longer pass, and when removing the rod the load from this side distributes throughout the equipment, therefore it has a load of the same magnitude as the rod

Electroscope 2

In this case, the equipment is touched, so the load redistributes in the two, when separating it remains with half the load of the cheek.

After analyzing each device separately we can answer the questions.

a) If both are charged

b) the first team has a load and the second half of it

c) The first team has a charge contrary to the rod, it is charged by induction and the second team has a charge equal to the rod, it is charged by contact