The electromagnet shown below is made up of a coil of electrical wire wrapped around an iron core.

Which of the following would decrease the strength of this electromagnet?

A adding batteries to the circuit

B removing its iron core

C increasing the current through the coil

D increasing the number of wire loops in the coil

B. Removing its iron core

Explanation:

In an electromagnet role of its core is very important as it concentrate magnetic flux to make magnetic field more powerful. Generally core of electromagnet is made up of a ferromagnetic material or of a ferrimagnetic material such as iron. Adding batteries to the circuit and increasing the current through the coil and increasing loops in the coil will increase magnetic strength of an electromagnet.