Question

The diagram shows a coil of copper wire wrapped around an iron cylinder and connected to a battery.

Answer 1

They can use the temporary magnetic field it creates to pick p a metal clip.

Explanation:

When a copper wire is wound around an iron cylinder and current is passed through the wire, the wire wound cylinder acts like a magnet. It is known that a current carrying wire develops  a magnetic field around it. This is the magnetic effect of electric current.

When the current carrying wire is wound around a cylinder it will become similar to a solenoid which is a device that continuously produces magnetic field on passing current through it.  

The magnetic field will cease existing once the current supply is cut off and thus it is temporary.