A student wishes to map the shape and direction of a bar magnet’s field. The table shows four methods.
| Method | Magnet position | Compass readings | Arrows added using |
|---|---|---|---|
| P | Fixed | One traced path | North-seeking end |
| Q | Fixed | Several traced paths | South-seeking end |
| R | Fixed | Several traced paths | North-seeking end |
| S | Changed between readings | Several traced paths | North-seeking end |
Which method is best, and why is method Q unsuitable?
S is best; Q reverses the field direction.
R is best; Q reverses the field direction.
R is best; Q changes the field strength.
S is best; Q changes the field strength.