Unit of Conductivity

The conductivity of any substance is its capacity to transfer electricity through ions. It can be of different variations, such as ionic, thermal or electrical. The electrical conductivity unit measures the current flow through an electrolyte solution.

What is a Unit of Conductivity?

The SI unit of conductivity measures the frequency at which a current or heat passes through any object. The universal measure for conductance is Siemens for per meter or S/m for any substance. It is also equal to ohm^-1*m^-1 when heat waves or thermal energy flows through a material.

It is also represented through the Greek letter σ. Its formula is:

σ = 1/ρ

Where σ = reciprocal of resistivity, while ρ = resistivity of an object.

Electrical conductivity occurs when a current flows in response to the forces acting upon them in an electric field. It is a measure of the amount of electrically charged particles that a material can transfer. The electronic conduction that flows through most particles depends on the number of electrons present in an object. 

Metals are an excellent conductor of electricity because it contains a large number of free electrons that can carry current within that material.

Fun Fact: Silver is the most conductive among all other metals, followed by copper and gold.

The SI unit of electrical conductivity, is defined as its ratio between current density (J) and intensity for an electric field (e).

S = J/e

Similarly, in water, conduction occurs through a free flow of ions. Though pure water does not help in conducting an electric current, distilled water and seawater allows conduction via electronically charged ions. This phenomena occurs due to the presence of minerals in distilled water and seawater. With an increase in the condensation of ions, there is an increase in conductivity.

Resistance and Conductivity Relationship

Resistance is a material property that restricts the flow of electrons in it. Consider a situation where there is a tunnel and water. Easier the water flows through a tunnel, the lower resistance it contains.

However, conductivity enables a free flow of electronically charged particles quickly through a material. The SI unit of conductivity is precisely the reverse of the SI unit of resistance. 

The formula of resistance is: R = ρ*l/A

Where ρ = resistivity.

A = cross section area

L = length of a wire

R = wide resistance

However, there is a link between conductivity and resistance. A good conductor is any material that offers little resistance when electricity flows through it. If a substance has less resistivity to thermal energy or heat, it implies that it has great conduction or vice versa.

Multiple Choice Questions

Here are some solved questions on the SI unit of conductivity. Read them and expand your knowledge.

  1. Conductivity is an Object’s Ability to Transmit 

  1. Current

  2. Voltage

  3. Resistance

  4. All the above points

Answer: a


  1. Which Reagent has a Specific Conductance?

  1. HCl

  2. Potassium chloride

  3. Sodium chloride

  4. Magnesium chloride

Answer: b


  1. The Universally Recognised SI Unit of Electric Conductance is

  1. Ohm

  2. Watt

  3. Siemens

  4. Joule

Answer: c


  1. Which of the Following Objects have a High Conductance?

  1. Plastic

  2. Water

  3. Glass

  4. Copper

Answer: d


  1. The Reverse of Conductivity is

  1. Resistivity

  2. Turbidity

  3. Viscosity

  4. None of these

Answer: a


The field of conductivity is vast and understanding what is the unit of conductivity requires in-depth knowledge. You can now download our Vedantu app to access detailed study material, as well as online classes to understand these concepts in detail.

FAQ (Frequently Asked Questions)

1. What is the Unit of Conductivity of Water?

Ans. Distilled water with carbon dioxide infused in it has a conductivity unit which is approximately 10*10-6 W-1*m-1 (20dS/m). Drinking water conducts electricity with 0.005 – 0.05 S/m.

What is the SI Unit of Conductivity for an Object?

Ans. The SI unit of conductance is Siemens for per meter or S/m applicable to any substance. Its symbol is denoted as K as per electrical engineering, and electrical conductivity has a symbol of sigma (σ).

How Does Conductivity Get Measured?

Ans. One can measure SI unit of conductivity with the help of meters and probes. The amount of resistance of a solution determines the conductivity of an object.