Compare two places by field strength

Where does the sphere's field push a charged bead the hardest?

One drawing holds two places. Which place sits in the stronger field? The gaps between the lines answer it, and this lesson is practice until that read is automatic.

The rule is one sentence: where field lines are closer together, the field is stronger. The drill is applying it fast, drawing after drawing.

Here is the read, on a star's field with a point P marked.

Small gaps next to the star, wide gaps out at P: the field is stronger where the gaps are small.

First, find the two places being compared. Here, that is the space right next to the star, and the space around P.

Second, compare the gaps between neighboring lines at each place. Next to the star, the lines sit close together. Out at P, the same lines have spread apart.

Third, give the verdict: the place with the smaller gaps sits in the stronger field. Here, that is the space next to the star.

If the gaps match everywhere, the strength matches everywhere: no difference in the gaps means no difference in strength. That even-spacing case is the one that catches people.

In a field drawn with straight, evenly spaced lines, is the field stronger at the top of the drawing or at the bottom?

The gaps between lines are the same at the top and at the bottom.

Matching gaps mean matching strength.

Neither. The field is equally strong at both.

Where is the field stronger?

Your turn

The drawing shows the field around a star, with point P marked. Which statement about the field strength is correct?

The drawn lines are straight, evenly spaced, and all point the same way. Which statement about the field strength is correct?

The drawing shows a bar magnet's field. Where is the field the strongest?