An electromagnet is a type of magnet in which the magnetic field is produced using the current. The simplest form of an electromagnet is a wire wrapped around in a coil.
The strength of magnetic field of such magnet is given with this equation:

Where N is the number of loops in the coil, I is the strength of the current flowing through the coil, L is the length of the coil, and

is <span>permeability of the electromagnet core material.
From this equation, we can see that increasing both the current and number of loops will increase the strength of the magnet.
Both BLANKS should be
Increase. When you use the additional battery you will have more voltage and more voltage means more electricity.</span>
The dog’s speed is
A) 0.61 m/s
Fperson =[( velocity of wind )+ or - (velocity of person)] / [(velocity of wind) + or - (velocity of sounds)] x frekuency of sounds