This equation states that the current density is proportional to the gradient of electric potential or, alternatively, the product of (*)  conductivity and the electric field.
Alfvén's  (all-VANE's)  theorem uses the idealized form of this law to prove that magnetic field lines exactly coincide with the streamlines in a plasma. In a common analogy, this equation is compared to Fourier's law for heat transport and Fick's law for mass transport. The three different expressions for Joule heating are interchangeable by using this equation. This equation states that the current density is proportional to the gradient of electric potential or, alternatively, the product of (*)  conductivity and the electric field. After applying Kirchhoff's loop and junction rules to reduce a circuit, you can use this equation to predict the current through a battery. For 10 points, identify this equation, often written as "V equals IR," whose German namesake also identifies the SI unit of resistance.
Alfvén's  (all-VANE's)  theorem uses the idealized form of this law to prove that magnetic field lines exactly coincide with the streamlines in a plasma.
 Ohm 's law 