A battery with [tex]15[/tex] loops or wire around the nail have the stronger force.
So, option 4 is correct.
Define electromagnet.
An electromagnet is a system that contains of a magnetic encircled by a coil that conducts an electric current to ionize the core.
Wherever controllable magnetism are required, such as in devices where the magnetic flux must be adjusted, reversed, or turned on and off, an electromagnet is utilized.
A battery with [tex]15[/tex] loops or wire around the nail have the stronger force.
So, option 4 is correct.
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