Question:medium
Consider two cuboidal blocks of volume 1 cm\(^3\) each, one made of gold and the other of undoped silicon. What will happen to the resistivity of these blocks if the temperature is increased from 300 K to 350 K? Choose one of the following.
Consider two cuboidal blocks of volume 1 cm\(^3\) each, one made of gold and the other of undoped silicon. What will happen to the resistivity of these blocks if the temperature is increased from 300 K to 350 K? Choose one of the following.
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A simple rule to remember: For metals, Temperature \(\uparrow\) \(\implies\) Resistivity \(\uparrow\). For semiconductors, Temperature \(\uparrow\) \(\implies\) Resistivity \(\downarrow\).
Updated On: Feb 14, 2026
- Resistivity of gold increases and undoped silicon decreases
- Resistivity of gold decreases and undoped silicon increases
- Resistivity of gold remains same and undoped silicon increases
- Resistivity of gold decreases and undoped silicon remains same
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The Correct Option is A
Solution and Explanation
Step 1: Concept:
Electrical resistivity depends on charge carrier concentration and mobility. The temperature effect differs for metals and semiconductors.
Step 2: Behaviour of Gold (Metal):
In metals, the number of free electrons remains almost constant with temperature. When temperature increases, lattice vibrations increase, which causes more scattering of electrons and reduces mobility. As a result, resistivity increases with temperature.
Step 3: Behaviour of Undoped Silicon (Intrinsic Semiconductor):
In intrinsic semiconductors, increasing temperature generates more electron-hole pairs. This significantly increases the carrier concentration, which increases conductivity and decreases resistivity, even though mobility slightly reduces.
Final Conclusion:
Therefore, with an increase in temperature, the resistivity of gold increases, while the resistivity of undoped silicon decreases.
Electrical resistivity depends on charge carrier concentration and mobility. The temperature effect differs for metals and semiconductors.
Step 2: Behaviour of Gold (Metal):
In metals, the number of free electrons remains almost constant with temperature. When temperature increases, lattice vibrations increase, which causes more scattering of electrons and reduces mobility. As a result, resistivity increases with temperature.
Step 3: Behaviour of Undoped Silicon (Intrinsic Semiconductor):
In intrinsic semiconductors, increasing temperature generates more electron-hole pairs. This significantly increases the carrier concentration, which increases conductivity and decreases resistivity, even though mobility slightly reduces.
Final Conclusion:
Therefore, with an increase in temperature, the resistivity of gold increases, while the resistivity of undoped silicon decreases.
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