Q:

Biot-savart's law for magnetic field

In my textbook under the subtopic
Similarities between biot-savart's law and Coulomb's law
It is written that the magnetic field is linear in its source Idl , just as the electric field is linear in its source , the electric charge
I'm unable to understand this point

A:

Linear means that if you consider a combination of sources such as $\alpha_1I_1+\alpha_1I_2$, you will obtain the corresponding combination of magnetic fields $\alpha_1B_1+\alpha_2B_2$.

