Question

object a and object b are insulators. object a has a positive charge. object b is neutral. object b is touched to the ground. when the ground is pulled away, what charge do the two objects have? key
□ = conductor
■ = insulator
tap to toggle through possible options for type of charge:
type of charge on a: tap here.
type of charge on b: tap here.

Explanation:

Step1: Analyze Object A (Insulator)

Insulators do not allow charge to move freely. Object A is an insulator with a positive charge. Since it's an insulator, its charge distribution doesn't change due to the presence of Object B or grounding (as insulators don't conduct charge to/from ground in the same way conductors do). So, Object A remains positively charged.

Step2: Analyze Object B (Insulator, Grounded)

Object B is an insulator, initially neutral. When touched to the ground, but since it's an insulator, charge from the ground (or to the ground) doesn't move freely onto/from B. Wait, but maybe the key here is that insulators can have charge redistribution via induction? Wait, no—insulators don't allow charge to move, but when a charged insulator (A) is near a neutral insulator (B), and B is grounded (but B is an insulator, so grounding B (an insulator) doesn't allow charge to flow. Wait, maybe the diagram or the problem has a mistake, but assuming that maybe the objects are conductors? No, the key says gray is insulator. Wait, no—maybe the problem is about induction in insulators? Wait, no, insulators can't have charge flow, but when a charged object (A, positive) is near B (neutral insulator), and B is grounded (but as an insulator, B can't conduct, so maybe the ground connection is via a conductor? Wait, the hand is touching B, maybe the hand is a conductor? Wait, the key says the gray boxes are insulators (A and B), and the white is conductor. So A and B are insulators, hand is a conductor (white? No, the key's white is conductor, gray is insulator. The hand is yellow, maybe the hand is a conductor. So when the hand (conductor) touches B (insulator), and B is near A (positive insulator). Wait, insulators can have polarization, but not charge transfer. But if B is touched to ground (via the hand, a conductor), but B is an insulator, so charge can't flow onto B. Wait, maybe the problem is mislabeled, and A and B are conductors? But the key says gray is insulator. Alternatively, maybe the question is about what happens when an insulator is grounded near a charged insulator. But insulators don't allow charge to move, so Object A remains positive (since it's an insulator, its charge doesn't change). Object B, being an insulator, even when grounded, can't gain or lose charge (since it's an insulator), but wait, no—maybe the induction in insulators: when a positive charge is near, the electrons in B (insulator) are slightly attracted, but since it's an insulator, they can't move freely. But when grounded, maybe the ground (a large conductor) can have charge induced, but B is an insulator, so B itself doesn't gain charge. Wait, this is confusing. But maybe the intended problem is that A and B are conductors, but the key is mislabeled. Alternatively, maybe the answer is: Object A remains positive (since it's an insulator, charge doesn't change), Object B remains neutral? But that can't be. Wait, no—maybe the problem is that even though they are insulators, the act of grounding (via the hand, a conductor) allows charge to flow onto B? No, B is an insulator. I think there's a mistake, but assuming that the problem is intended to have A and B as conductors (maybe the key is wrong), then: If A is a positive conductor, B is a neutral conductor, B is grounded. Then A remains positive, B becomes negative (due to induction: electrons from ground flow onto B). But since A and B are insulators, maybe the answer is A: Positive, B: Neutral? No, that doesn't make sense. Wait, the key says A and B are insulators. So insulators can't have charge flow. So Object A, being an insulator with positive charge, keeps its positive charge. Object B, being an insulator, even when grounded, can't gain or lose charge (since it's an insulator), so remains neutral. But that seems odd. Alternatively, maybe the problem is about what happens when an insulator is grounded near a charged insulator. But insulators don't allow charge transfer, so A is positive, B is neutral. But that seems too simple. Wait, maybe the hand is a conductor, so when the hand touches B (insulator), and B is near A (positive), the hand (conductor) can have charge flow, but B is an insulator, so B itself doesn't get charge. But the question is about the charge on A and B. So A: Positive (since it's an insulator, charge doesn't change), B: Neutral (since it's an insulator, can't gain/lose charge via grounding). But I'm not sure. Alternatively, maybe the problem has a typo, and A and B are conductors. If they were conductors: A is positive, B is neutral, B is grounded. Then A remains positive (charge can't leave A as it's isolated? No, if A and B are conductors and touching? No, A and B are separate (the diagram shows A and B as separate gray boxes, insulators). So I think the intended answer is: Type of Charge on A: Positive, Type of Charge on B: Neutral. But that seems off. Wait, no—maybe the problem is that when you ground B (even as an insulator), the ground (a large conductor) can have charge induced, but B itself, being an insulator, doesn't gain charge. So A remains positive, B remains neutral.

Answer:

Type of Charge on A: Positive
Type of Charge on B: Neutral