Could someone EXPLAIN the answers to these multiple choice questions please? I b
ID: 2276984 • Letter: C
Question
Could someone EXPLAIN the answers to these multiple choice questions please? I believe I have them right but i need an explaination
Sphere A carries a net charge and sphere B is neutral. Both are conducting spheres
and they are placed near each other on an insulated table. Which statement best describes
the electrostatic force between them?
a) There is no force between them since one is neutral.
b) There is a force of attraction between them. 0 I believe B is correct
c) There is a force of repulsion between them.
d) The force is attractive if A is charged positively and repulsive if A is charged
negatively.
Sphere A carries a net positive charge and sphere B is neutral. Both are conducting
spheres and they are placed near each other on an insulated table. Sphere B is briefly
touched with a wire that is grounded. Which statement is correct after the ground wire is
removed?
a) Sphere B remains neutral.
b) Sphere B is now positively charged.
c) Sphere B is now negatively charged. - i know it is C is correct
d) The charge on sphere B cannot be determined without additional information.
Explanation / Answer
1) Yes (b) is correct because when the neutral sphere is brought close to the charged sphere, the region of the neutral sphere that faces the charged sphere get a net charge becuase either the electrons are repelled to the backward region or attracted from the backward region of neutral sphere or attracted (depends on the charged sphere, whether negative or positive). In this condition, still the net charge on the neutral sphere is zero but the distribution gets biased, hence there is always a attractive force.
2) Yes (c) is correct. This connditon is the extension of above explanation. When the neutral sphere is grounded, the charge that was making the sphere neutral, now goes to earth and opposite charge will exist in the neutral sphere. As, in given question, charge on chrged sphere is positive, hence the neutral sphere will be finally charged with negative charge because positive charge will flow out to the ground (actually extra electrons come from the ground to neutralise the created positive charge due to biased distribution)