Question

When a coil is placed in a constant external magnetic field directed perpendicular to the plane of the coil, which of the following actions does not induce an emf in the coil?

moving the coil through the field without changing its orientation with respect to the field
removing the coil from the field
rotating the coil
collapsing the coil
changing the strength of the magnetic field

Answer 1

moving the coil through the field without changing its orientation with respect to the field

Step-by-step explanation:

An emf can only be induced in the coil by whatever action that causes a change in the flux through the coil.

The following descriptions all change the flux through the coil and induce

an emf:

removing the coil from the field

rotating the coil

collapsing the coil

changing the strength of the magnetic field

However, moving the coil through the constant field without changing its orientation with respect to the field will not cause a change of flux. Hence the chosen answer.

Answer 2

The actions that does not include an emf in the coil should be moving the coil through the field without changing its orientation with respect to the field.

What is emf:

An emf can only be induced in the coil at the action that leads the change in the flux via the coil. The explanation where all change the flux via the coil and induce and emf in the way when the coil should be removed, the coil should be rotated, the coil should be collapsed, also the strength of the magnetic field should be changed.

Therefore, the first option is correct.