Question

Your group has the following equipment: An electroscope, a foam tube, fur, a small plastic cup, a small metal cup. You perform the experiments described below and record the outcomes. For each of the experiments, use your understanding of the electric field to explain why each outcome happened.

-Make sure your explanations use the concept of the electric field rather than “opposite charges attract/same charges repel” ideas.

-Draw LARGE charge diagrams to illustrate your explanations. Show the shape of the electric field by including electric field lines.

Experiments:

a. Bring the charged end of a foam tube down toward the top of an uncharged electroscope without touching the electroscope. Outcome: The metal strips separate.

b. Take the charged end of the foam rod away from the top of the uncharged electroscope. Outcome: The metal strips come back together

c. Repeat the first two experiments, only this time a metal can covers the electroscope but doesn’t touch it. Outcome: The metal strips do not separate.

d. Repeat the first two experiments, only this time a glass beaker covers the electroscope but doesn’t touch it. Outcome: The metal strips separate then come back together, but much less significantly than in experiments a. and b.

Answer 1

ELECTROSCOPE:- it is a device used to detect the presence of electric charge in a body.

(b) when we take the charged foam tube away , so the strips become neutral because the negative charge which was accumulated on the top would nullify the positive charge of plate as there is no external field which induce the negative charge on the top of the electroscope and overall the electroscope is neutral.

(d)

glass beaker is insulator so it wont affect the electric field and electric field would flow like in first case as when charged part the foam comes near the electroscope the metal strip move away. .