V = IR Equation & I-V Graphs

Let's take some amps and some ohms, and take 4a (4 amps), and 2Ω(ohms).

We would multiply the 4a * 2Ω, and it would be 8v or 8 volts, so if we take a 24v battery and it is producing the current of 8a, then it would be 24v/8a which would be 3Ω or 3 ohms.

Let's make a graph, shaped like a plus sign, and let's put the top number I for the current, and V for the differential difference. 
And it's a very straight line, a straight 45° incline. Now along as we are using wires and resistors that line will be very straight, but now if we add more resistors, the incline changes to around 25°, or if we use less it would be a more 75° incline. 

Now what about Filament lamps and Diodes, filament lamps work by heating up via electricity allowing them to emit light, now if we put in a lot of electricity to let the lamp glow, it starts to be weaker the more power we put in it since when the lamp heats up it increases resistance.

Now Diodes only work when the current is positive, how it works is they have they have a really strong resistance to negative currents.