Definition:Resistance

Definition

Resistance is a measure of how difficult it is to pass an electric current through a conductor.

It is defined as the electromotive force needed to push a unit current through that conductor.

It is conventionally denoted $R$.

Symbol

$R$

The usual symbol used to denote resistance is $R$.

Its $\LaTeX$ code is R .

Dimension

The dimension of measurement of resistance is:

$\mathsf {M L^2 T^{−3} I^{−2} }$

This derives from its definition as:

$R = \dfrac {\text {EMF} } {\text {current} }$

Unit

The SI unit of resistance is the ohm $\Omega$: $1 \, \Omega = 1 \, \mathrm V \, \mathrm A^{-1}$

In the CGS unrationalised electromagnetic system, the base unit of resistance is the abohm $\mathrm {ab\Omega}$.

In the CGS unrationalised electrostatic system, the base unit of resistance is the statohm $\mathrm {stat\Omega}$.

Conversion Factors

\(\ds \)

\(=\)

\(\ds 1\)

ohm

\(\ds \text {corresponds to}\)

\(\)

\(\ds 10^9\)

abohm (or e.m.u. of resistance)

\(\ds \text {corresponds to (approximately)}\)

\(\)

\(\ds \dfrac 1 9 \times 10^{-11}\)

statohm (or e.s.u. of resistance)

Also see

• Results about resistance can be found here.

Sources

• 1969: J.C. Anderson, D.M. Hum, B.G. Neal and J.H. Whitelaw: Data and Formulae for Engineering Students (2nd ed.) ... (previous) ... (next): $1.$ Units and Abbreviations: $1.2$ SI units $(2)$ Derived units