# Resistance current and voltage

• drinkingstraw
In summary, resistance is the measure of opposition to the flow of current in a circuit, represented by the symbol R and measured in Ohms (Ω). According to Ohm's Law, it is directly proportional to voltage and inversely proportional to current, with voltage remaining constant. Factors such as length, cross-sectional area, and temperature of a material affect resistance, as well as its type and composition. The formula for calculating resistance is R = V/I, and it differs from impedance, which takes into account both resistance and reactance in AC circuits.

#### drinkingstraw

I was wondering what the difference in current would be in one full extension cord versus several extension cords (which equal the same length as the first) attatched together?

I was thinking there would be more resistance when the current goes from one cord to another but I'm not sure

There is a very tiny amount of contact resistance (assuming well-maintained cords of the proper rating), but the difference is so small as to have no practical importance.

## What is resistance?

Resistance is the measure of opposition to the flow of current in a circuit. It is measured in Ohms (Ω) and is represented by the symbol R.

## How is resistance related to current and voltage?

According to Ohm's Law, resistance is directly proportional to voltage and inversely proportional to current. This means that as resistance increases, current decreases, and as resistance decreases, current increases. Voltage remains constant.

## What factors affect resistance?

Resistance is affected by the physical properties of a material, such as its length, cross-sectional area, and temperature. It is also influenced by the type of material and its composition.

## How do you calculate resistance?

The formula for calculating resistance is R = V/I, where R is resistance in Ohms, V is voltage in volts, and I is current in amperes. This formula can also be rearranged to calculate voltage or current when the other two values are known.

## What is the difference between resistance and impedance?

Resistance and impedance are similar in that they both measure opposition to current flow, but they are not the same. Resistance is the opposition to direct current (DC) flow, while impedance is the opposition to alternating current (AC) flow. Impedance takes into account both resistance and reactance (the opposition to AC flow caused by capacitance and inductance).