Introduction
 

Resistivity is a property of materials that determines how strongly they oppose the flow of electric current. Unlike resistance, which depends on the dimensions of a conductor, resistivity is an intrinsic property of the material itself. Understanding resistivity allows students to compare different conducting materials and investigate how resistance changes with length, cross-sectional area and temperature.

This topic also introduces superconductors—materials that have zero electrical resistance below a critical temperature. Superconductivity has many important technological applications, including MRI scanners, particle accelerators and magnetic levitation (maglev) trains.
 

AQA A Level Physics Specification: 3.2.4.2 Resistivity
 

What You Need to Know
 

• Define resistivity as an intrinsic property of a material.

• Understand the relationship between resistance, resistivity, length and cross-sectional area.

• Apply the equation:

  R = ρL / A

• Calculate the resistance of a conductor using its dimensions and resistivity.

• Understand how the resistance of metallic conductors changes with temperature.

• Describe the properties of superconductors.

• Explain the meaning of critical temperature.

• Understand that superconductors have zero electrical resistance below their critical temperature.

• Describe practical applications of superconductors, including MRI scanners, particle accelerators, maglev trains and efficient power transmission.

• Discuss the advantages and limitations of superconductors in real-world applications.
   

Downloadable Topic Pack
 

Resistivity & Superconductors Topic Pack Exam Questions and Answers
 

Related Topics
 

• IV Characteristics and Electricity Basics

• EMF & Internal Resistance

• Potential Divider

• Electromotive Force (EMF)

• Practical Investigation of Resistivity