Which of the Following Is Essential for the Laser Action

question 39

Multiple Choice

Which of the following is essential for the laser action to occur between two energy levels of an atom?

• A)the lower level is metastable
• B)there are more atoms in the upper level than in the lower level
• C)there are more atoms in the lower level than in the upper level
• D)the lower level is the ground state
• E)the lasing material is a gas

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Definitions:

Equation

A mathematical statement that asserts the equality of two expressions.

Genetic Equilibrium

A state in which the frequency of alleles in a population remains constant over time, assuming no evolutionary forces are at work.

Allele Frequency

The relative frequency of an allele (variant of a gene) at a particular gene locus in a population, expressed as a fraction or percentage.

Heterozygous Individuals

Organisms having two different alleles for a specific gene, one inherited from each parent.