Semiconductors: the Energy Gap Between the Valence and Conduction Bands

question 21

Multiple Choice

Semiconductors: The energy gap between the valence and conduction bands in a certain semiconductor is 1.25 eV. What is the threshold wavelength for optical absorption in this substance? (c = 3.00 × 10⁸ m/s, 1 eV = 1.60 × 10^-19 J, h = 6.626 × 10^-34 J ∙ s)

• A) 599 nm
• B) 639 nm
• C) 959 nm
• D) 873 nm
• E) 994 nm

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Definitions:

CNS

Central Nervous System, the part of the nervous system consisting of the brain and spinal cord, which integrates and coordinates bodily functions.

Event-Related Potentials

Brain waves measured by EEG that are the direct result of a specific sensory, cognitive, or motor event, useful in the study of cognitive processes.

Electroencephalogram

A test that measures electrical activity in the brain using small, flat metal discs attached to the scalp.

ERPs

Event-Related Potentials; brain responses that are directly the result of a specific sensory, cognitive, or motor event.