MCQ Detailed View

The electrical conductivity of metals depends on how easily free electrons can move through the metallic lattice. In metals, atoms are arranged in a crystalline structure, and each atom contributes free electrons that can move freely. These free electrons are the charge carriers responsible for the high conductivity of metals like copper, silver, aluminum, and iron.

When the temperature of a metal rises, its atoms start vibrating more intensely. This increased lattice vibration creates frequent collisions between the free electrons and the vibrating ions. As a result, the flow of electrons is hindered, and the resistance of the metal increases. Since electrical conductivity is the inverse of resistance, an increase in resistance leads to a decrease in conductivity.

This effect is a well-established property of metals. For example, copper at room temperature has excellent conductivity, but when its temperature increases significantly, its conductivity drops. This is why electrical transmission lines made of aluminum or copper heat up under high current load, causing higher energy losses.

Mathematically, this relationship is expressed as:

RT=R0(1+αΔT)R_T = R_0 (1 + \alpha \Delta T)RT=R0(1+αΔT)

Where:

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  RTR_TRT = resistance at temperature T

  
  


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  R0R_0R0 = resistance at reference temperature

  
  


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  $\alpha$ = temperature coefficient of resistance

  
  


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  $\Delta T$ = change in temperature

  
  

Since resistance increases with temperature in metals, conductivity decreases.

It is important to note that this behavior is specific to metals. In semiconductors, the opposite happens — conductivity increases with rising temperature because more electrons gain enough energy to jump into the conduction band.

In conclusion, with the rise in temperature, the electrical conductivity of metals decreases, due to increased resistance from atomic vibrations interfering with the motion of free electrons. This principle is crucial in physics, electrical engineering, and materials science.