physics question

[wlee43]

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1)If the conducting electroscope were replaced by an insulating ball and then charged by induction as above(referring to previous question which is A negatively charged rod is brought near an electroscope), what would be the net charge on the ball?

pos, zero or neg

Bottom two questions are confusing because of the figure (attached below) and the question is not specific enough in my opinion



2)What is the direction of the net force on the dipole?

left ,zero or right

3)What is the direction of the force of the electric field on a NEGATIVE charge? (Refer to the figure in the question 2)

left, right, or up

 

[milski]

1) Not sure which ball are they talking about. If the dipole on the right was not charged and then they brought the big negatively charged sphere next to it, the net charge on it will still be zero.

2) To the left. If the dipole was not charged at the beginning, the positive and the negative charge have the same magnitude. The positive is closer to the negatively charged ball on the left and the attraction force between +/- will have larger magnitude then the repelling between -/-.

3) Not very sure about the setup here. Are they talking about the same thing as the attached figure?

All these assume a lot which is not explicitly said in the question, so details would help.

 

[wlee43]

The first question is not related to the figure

 

[wlee43]

1) Not sure which ball are they talking about. If the dipole on the right was not charged and then they brought the big negatively charged sphere next to it, the net charge on it will still be zero.

2) To the left. If the dipole was not charged at the beginning, the positive and the negative charge have the same magnitude. The positive is closer to the negatively charged ball on the left and the attraction force between +/- will have larger magnitude then the repelling between -/-.

3) Not very sure about the setup here. Are they talking about the same thing as the attached figure?

All these assume a lot which is not explicitly said in the question, so details would help.

For question 2 and 3 they are talking about the figure. However I don't know what the question is trying to ask because there is two negative charges in the figure 😡

 

[milski]

For question 2 and 3 they are talking about the figure. However I don't know what the question is trying to ask because there is two negative charges in the figure 😡

Ok, answer for 2 still stands.

3 - if the question is really that poorly worded, I would go with 'right.' That assumes that they are talking about the electric field created by the big sphere on the left and either the negatively charged end of the dipole or a negative charge inside the dipole itself. The latter seems a bit more likely since they talk about a negative charge.

I have a feeling that they are mostly focusing on the inductive charging and how the presence of the big sphere affects the charges along the dipole.

 

[wlee43]

The answer is left for number three. Does this mean they are talking about the righmost charge? This is the most poorly written question ever

 

[milski]

The answer is left for number three. Does this mean they are talking about the righmost charge? This is the most poorly written question ever

That would match the answer. What's the source of the question? I agree with you that it's very poorly written.