What is the relationship between resistivity of a wire and length of a wire is?

​

Explanation:

The relation between length and resistivity is given by the resistivity formula, i.e, ⍴ = R/L. Resistance varies directly with the length of the wire. It means that any variation in the length of the material will change the value of resistance (or resistivity).

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.

beta is electron from nucleus

something from nucleus has changed, but charge must be same for cons of charge