Answer:

Explanation:
As we know that the magnetic field near the center of solenoid is given as

now we know that initially the length of the solenoid is L = 18 cm and N number of turns are wounded on it
So the magnetic field at the center of the solenoid is 2 mT
now we pulled the coils apart and the length of solenoid is increased as L = 21 cm
so we have

now plug in all values in it


<span>The career that is most concerned with the study of radioactive isotopes is chemistry. You need to have passed AP chemistry to actually deal with the isotopes. In a quick reference, isotopes are when the atom has difference amount of neutrons, making the atomic mass differ.</span>