An iron core is needed in an electromagnet because it serves to increase the magnetic field created. It has a ferromagnetic properties. <span>An </span>electromagnet<span> is essentially just a battery attached to a coil of wire wrapped around a metal</span>core<span>. </span>
Answer:
by using it in a such place or thing which needs it or which can work with it
The entire mass of the Earth at neutron star density would fit into a sphere of 305 m in diameter
It would be a neutral,
The acidity of water is 7 as well