When temperature increases, the electrical conductivity of a semiconductor?

Appeared in: KPSC Staff Nurse - 2015

Explanation

In a semiconductor, an increase in temperature provides thermal energy to the electrons.
This energy excites electrons from the valence band to the conduction band, creating free electrons and holes.
Both electrons and holes act as charge carriers, and their increased number leads to a significant increase in electrical conductivity.
This property is fundamentally different from metals, where conductivity decreases with temperature.

Option B: A decrease in conductivity with increasing temperature is characteristic of metals, not semiconductors. In metals, higher temperature increases atomic vibrations, which impedes the flow of electrons.
Option C: The conductivity of a typical semiconductor increases monotonically with temperature over a wide range. It does not normally decrease after an initial increase under standard operating conditions.
Option D: The electrical conductivity of a semiconductor is strongly dependent on temperature. A change in temperature causes a significant, predictable change in the number of charge carriers.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Temperature dependence of semiconductor conductivity as background academic context rather than a clinical decision trigger.
The principle of semiconductor conductivity is the basis for thermistors, which are essential for temperature monitoring in clinical practice.
Nurses frequently use devices with thermistors, such as electronic thermometers (oral, rectal, axillary), temperature probes for continuous core temperature monitoring in critically ill patients, and sensors in infant incubators.
Understanding this principle helps in appreciating the technology behind vital sign monitoring and troubleshooting potential equipment issues.

How to Approach the Question

Identify the core concept being tested: the relationship between temperature and conductivity.
Identify the material type: the question specifies a 'semiconductor'.
Recall the fundamental properties of semiconductors versus metals. In semiconductors, thermal energy creates charge carriers.
Contrast this with metals, where thermal energy increases resistance.
Conclude that for a semiconductor, increasing temperature will increase the number of charge carriers and thus increase conductivity.
Select the option that matches this conclusion.

Concept Tested & Keywords

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Practise the full KPSC Staff Nurse - 2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.