A=0.3mm, R=10 and L=?

I don't know what you are trying to do or where you got your terms.

Ohms law is a series of derivative formulas that let you calculate various pars of a circuit.

The base formula is E=IR where E represents voltage, I represents Amperage and the R represents the resistance of the circuit.

Using a derivative formula, I can determine the value of "I" when I know the values of "E" and "R".

for example I = E/R - - I = 12/6 I=2.

I hope I helped you.

What is A and L? Area and Length?
L can also be lambda.