A Laser Emits a Pulse of Light That Lasts 10

question 72

Multiple Choice

A laser emits a pulse of light that lasts 10 ns.The light has a wavelength of 690 nm,and each pulse has an energy of 480 mJ.How many photons are emitted in each pulse? (c = 3.0 × 10⁸ m/s,h = 6.626 × 10^-34 J ∙ s)

• A)1.7 × 10¹⁸
• B)2.1 ×
• C)2.6 ×
• D)3.1 ×

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Definitions:

Control Group

A group in an experiment that does not receive the experimental treatment and is used as a benchmark to measure how the other tested subjects do.

Random Sample

A selection process where each member of a population has an equal chance of being included in the sample, minimizing bias.

Population

In statistics and demography, a comprehensive group of individuals or items that share one or more characteristics from which data can be gathered and analyzed.

Double-blind Study

A study design in which neither the participants nor the researchers know which participants belong to the control group and which belong to the experimental group until the conclusion of the research.