Each of three objects has a net charge. Objects [tex]\(A\)[/tex] and [tex]\(B\)[/tex] attract one another. Objects [tex]\(B\)[/tex] and [tex]\(C\)[/tex] also attract one another, but objects [tex]\(A\)[/tex] and [tex]\(C\)[/tex] repel one another. Which one of the following table entries is a possible combination of the signs of the net charges on these three objects?

| A | B | C |
|----|----|----|
| + | - | - |
| - | + | + |
| + | - | + |
| - | + | - |



Answer :

To determine the possible combination of the signs of the net charges on objects A, B, and C, let's analyze the information given:

1. Objects A and B attract one another:
- For objects to attract, they must have opposite charges. Therefore, one of them must be positive and the other must be negative.

2. Objects B and C attract one another:
- Similarly, for objects B and C to attract, they must have opposite charges. Therefore, one of them must be positive and the other must be negative.

3. Objects A and C repel one another:
- For objects to repel, they must have the same charge. Therefore, both of them must be either both positive or both negative.

Now let's reason through this step-by-step:

- From the first point, if A and B attract, we can deduce:
- If A is positive, B must be negative.
- If A is negative, B must be positive.

- From the second point, if B and C attract, given that B is negative (from the first point), C must be positive. Or if B is positive, C must be negative.

- From the third point, if A and C repel, they must have the same charge. This means they both need to be positive or both negative.

Let’s piece these together:

1. Assume A is positive:
- Then from the first point, B must be negative.
- From the second point, if B is negative, C must be positive.
- From the third point, since A and C must both be positive and we assumed A is positive, this works out because we also determined C is positive.

2. Assume A is negative:
- Then from the first point, B must be positive.
- From the second point, if B is positive, C must be negative.
- From the third point, since A and C must both be negative and we assumed A is negative, this works out because we also determined C is negative.

So, a possible combination of the signs of the net charges on these three objects that satisfy all the given conditions is:
- A: Positive
- B: Negative
- C: Positive

Hence, the combination of signs of the net charges on objects A, B, and C is as follows:

A: +
B: -
C: +