Catch the wrong line on magnets

Exercise and reference answers

Questions

1. False statement

   Cutting a bar magnet in two frees a single north pole.

   Statements

   1. Cutting a bar magnet in two gives two smaller magnets.
   2. Cutting a bar magnet in two frees a single north pole.
   3. Magnetic field lines run in closed loops.

2. False statement

   The equatorial field is twice the axial field.

   Statements

   1. The equatorial field points opposite to the moment.
   2. The far field of a bar magnet falls as one over r cubed.
   3. The equatorial field is twice the axial field.

3. False statement

   Field lines stop abruptly at the surface of a magnet.

   Statements

   1. Field lines stop abruptly at the surface of a magnet.
   2. Net magnetic flux through any closed surface is zero.
   3. A needle is stable when its moment lies along the field.

Instructions

Each set of three lines about bar magnets carries one that is not correct. Tap that line.

Explanation