Question

which model represents the field lines around two negative ions?

Explanation:

Step1: Recall Electric Field Lines Rule

Electric field lines point towards negative charges (since field lines show the direction a positive test charge would move, so towards negatives). For two negative charges, they repel, so field lines around each negative charge point inward, and between them, field lines should curve away from each other (as like charges repel, so field lines don't connect the two negatives directly; instead, they curve to show repulsion).

Step2: Analyze Each Graph

- Top - Left: Field lines between the two negatives seem to be moving towards each other? No, wait, no—wait, the arrows: for negative charges, field lines point to the negative. Wait, no, let's check the direction. Wait, the first (top - left) graph: the arrows on the field lines between the two negatives—wait, no, actually, for two negative charges, the field lines should point towards each negative, and between them, since they repel, the field lines should curve away from the region between them (or rather, the field lines from each negative should curve such that they don't connect, and the space between has field lines curving outward? Wait, no, let's think again. The correct pattern for two negative charges: each negative has field lines pointing towards it, and between the two negatives, the field lines should be curved such that they are repelling—so the field lines from each negative will curve away from the other negative. Looking at the options, the Top - Left graph: the field lines between the two negatives—wait, no, the bottom - right? Wait, no, let's check the direction of arrows. Wait, the question is about two negative ions. So electric field lines point towards negative charges. Now, for two like charges (both negative), the field lines should repel each other. So between the two negatives, the field lines should curve away from the line connecting the two negatives. Let's look at the four graphs:

1. Top - Left: The field lines between the two negatives—wait, the arrows on the field lines between them: some are pointing towards each other? No, wait, no. Wait, the first graph (top - left) has two blue negative charges. The field lines from each negative: for the left negative, field lines point to it; for the right negative, field lines point to it. Between them, the field lines are curving, but do they show repulsion? Wait, no, the correct graph for two negatives: the field lines should be such that between the two, the field lines are curved outward (since the negatives repel, so the electric field in the region between them should be directed away from the mid - line? Wait, no, let's recall: for two positive charges, field lines repel and curve away; for two negative charges, field lines point towards each negative, and between them, the field lines are curved in a way that they are repelling—so the field lines from each negative will curve so that they don't connect, and the space between has field lines that are pushing away from each other. Wait, maybe I got the first graph wrong. Wait, the bottom - right graph: no, the bottom - right has arrows pointing away from the charges (which would be positive charges). Wait, no! Wait, the key is: electric field lines point towards negative charges, away from positive charges. So in the graphs, if the arrows point towards the blue circles (negative ions), then it's a negative charge. Now, for two negative charges (like charges), the field lines should repel. So between the two negatives, the field lines should curve away from each other (i.e., the field lines from the left negative will curve to the left of the mid - line, and from the right negative to the right of the mid - line, not crossing towards each other). Let's check each graph:

- Top - Left: The field lines between the two negatives: some field lines from the left negative and right negative are curving towards each other? No, wait, no. Wait, the top - left graph: the left negative has field lines pointing to it, the right negative has field lines pointing to it. Between them, the field lines are curving, but do they show repulsion? Wait, no, the correct graph is the Top - Left? Wait, no, wait the bottom - right graph has arrows pointing away from the charges (so that would be positive charges). The top - right and bottom - left have field lines connecting or curving towards the mid - line (which would be for opposite charges). Wait, no, I think I made a mistake. Let's start over.

Electric field lines:
- For a single negative charge: field lines point towards it.
- For two negative charges (like charges), the field lines will repel each other. So the field lines from each negative charge will curve such that they do not connect the two charges, and the region between the two charges will have field lines that are curved in a way that they are pushing away from each other.

Now, looking at the four graphs:

1. Top - Left: Two negative charges, field lines point towards each. Between them, the field lines are curved, but do they repel? Wait, the field lines from the left negative: some go to the left, some curve towards the right negative? No, wait, no. Wait, the top - left graph: the field lines between the two negatives—wait, the arrows on the field lines between the two negatives: for the left negative, field lines point to it; for the right negative, field lines point to it. The field lines between them: some are going from the left negative's vicinity towards the right negative, but since both are negative, that would be wrong? Wait, no, no—electric field lines are continuous (except at charges). Wait, no, the correct pattern for two negative charges is that the field lines point towards each negative, and between the two, the field lines curve away from the line connecting the two negatives (i.e., the field lines from each negative will curve so that they are repelling). The Top - Left graph: if we look at the field lines between the two negatives, they are curving in a way that they are moving away from the mid - line? Wait, maybe I was confused earlier. Let's check the direction of the arrows. In the Top - Left graph, all the arrows point towards the blue negative charges (since the arrows on the field lines are pointing towards the blue circles). Now, for two negative charges, the field lines should repel, so the field lines between them should be curved such that they don't connect, and the space between has field lines that are pushing apart. The Top - Left graph shows this: the field lines from each negative are curving, and between them, the field lines are not connecting, and the overall pattern is of repulsion (since like charges repel, and the field lines between them are curved in a way that they are moving away from the region between the two negatives? Wait, no, maybe the Top - Left is correct. Wait, the other graphs:

- Top - Right: The field lines are connecting the two negatives, which would be for opposite charges (attraction).
- Bottom - Left: Also has field lines connecting, which is attraction (opposite charges).
- Bottom - Right: The arrows point away from the blue circles, which would be positive charges.

So the correct graph is the Top - Left one (the first graph, top - left). Wait, but let's confirm. For two negative charges, electric field lines point towards each charge, and between the two charges, the field lines repel each other, so the field lines from each charge will curve away from the other charge. The Top - Left graph shows this: each negative has field lines pointing to it, and between them, the field lines are curved in a way that they are repelling (not connecting, and the field lines from each negative are curving so that they don't overlap in a way that suggests attraction).

Answer:

The Top - Left Graph (the first graph in the top - left corner)