EasyPhysicsHigh School (9–10)Electricity & Magnetism › Magnetic Effects of CurrentConceptualBoard Exam
In a drawing of a bar magnet's field, 15 lines cross a gap of 1 cm next to a pole, and 3 lines…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
In a drawing of a bar magnet's field, lines cross a gap of next to a pole, and lines cross a gap of far from the magnet.
- Where is the field stronger, and how many times as strong?
- Why can two field lines never cross?
Need a reminder? The key ideaShow
Field lines run from the north pole to the south pole outside a magnet, and back inside it, so they are closed loops. The field is strongest where the lines are closest together. Two lines never cross. A compass's north end points along the line through it.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. (a) More lines cross the same gap near the pole, so the field is stronger there: times as strong.
Step 2. (b) At a crossing, a compass needle would have to point along two lines at once. The field at a point has only one direction, so lines cannot cross.
Answer: (a) near the pole, times as strong. (b) The field has one direction at each point.
Check. The lines crowd together at the poles in every drawing of a bar magnet.
Discussion (0)
Log in to join the discussion.
Loading…