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Electricity and Magnetism

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Moderate

Experiment to Determine if a Material is an Electrical Conductor

EANDM-CDU4QE

You have an uncharged sphere of unknown material and you would like to determine if the material is an electrical conductor or insulator. You devise and perform the following experiment:

First, you touch the sphere with a negatively charged rod so that charge is transferred to the sphere as shown in figure a. Then, you bring a similarly charged rod, suspended from a string near (not touching) the sphere. The rod is repelled by the sphere.

Created for Albert.io. Copyright 2016. All rights reserved.

Based off this experiment, is the sphere an insulator or a conductor? Choose the best explanation for why.

A

This experiment is inconclusive; there is no way to tell if the sphere is a conductor or an insulator.

B

The sphere is an insulator. Insulators always repel negatively charged objects.

C

The sphere is an insulator. As the charge is transferred to the sphere, the electrons evenly distribute themselves along the surface so the entire surface of the sphere is negatively charges and thus the suspended rod is repelled.

D

The sphere is a conductor. As the charge is transferred to the sphere, the electrons evenly distribute themselves along the surface so the entire surface of the sphere is negatively charges and thus the suspended rod is repelled.

E

The sphere is a conductor. When the charge is transferred to the sphere, the electrons immediately move to the other side of the sphere and therefore the suspended rod is repelled.