A neutral (unchanged) metal ball is suspended using a non-magnetic string. A positively charged insulating rod is placed near the ball which is observed to be attracted to the rod. This is because

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Q: 47 (NDA-II/2011)
A neutral (unchanged) metal ball is suspended using a non-magnetic string. A positively charged insulating rod is placed near the ball which is observed to be attracted to the rod. This is because

question_subject: 

Science

question_exam: 

NDA-II

stats: 

0,1,8,3,5,1,0

keywords: 

{'metal ball': [0, 0, 0, 1], 'ball': [1, 3, 13, 12], 'electrons': [0, 0, 0, 5], 'rod': [1, 0, 0, 2], 'induction': [0, 0, 1, 1]}

Option 1: The ball becomes positively charged by induction.

When a positively charged rod is brought near the neutral metal ball, the electrons in the ball are attracted to the positive charge of the rod. This causes a temporary separation of charge in the ball, with the positive charges being attracted to the rod and the negative charges being repelled. However, this separation of charge does not result in the ball acquiring a net positive charge. Instead, the induced positive charges in the ball are closer to the rod, causing an overall attraction between the ball and the rod.

Option 2: The ball becomes negatively charged by induction.

This option is incorrect because, in induction, the separation of charge causes the ball to have induced positive charges, not negative charges.

Option 3: There is a rearrangement of the electrons in the ball.

When the positively charged insulating rod is brought near the ball, the electrons in the ball redistribute themselves. Some electrons are attracted to the rod, resulting in a temporary accumulation of positive charges in the ball. This rearrangement of electrons causes the ball to be attracted to the rod.

Option 4: The number of electrons in the ball is more than the number of electrons on the rod.

This option is incorrect because the number of electrons in the ball