The formula for ohm’s law can be written: v equals

a. l x r
b. l/r
c. r/l

The formula for Ohm’s law can be written: V equals  l x R

Option A

Explanation:

Ohm's law defines that an electric current flowing through the conductor between two ends is directly proportionate to the voltage at these two points. The introduction of a constant proportionality, resistance, gives a simple mathematical equation describing this relationship. Particularly, Ohm's law also mentions that R is constant in this respect i.e. independent on current.

Where,  

I is the current conduction in amperes

V is the voltage calculated by the conductor in volts

R is the conductor’s resistance in ohms.

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.

increases it