If a 20 W Laser Beam,which Has an Initial Diameter $\times$

question 22

Multiple Choice

If a 20 W laser beam,which has an initial diameter of 2.0 mm,spreads out to a diameter of 2.0 m after traveling 10,000 m,what is the initial E_rms of the beam?

• A) 4.9 \(\times\) 10⁴ V/m
• B) 2.5 \(\times\) 10³ V/m
• C) 1.2 \(\times\) 10³ V/m
• D) 1.9 \(\times\) 10² V/m
• E) 1.7 \(\times\) 10² V/m

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Definitions:

Deposited

The process by which sediments, minerals, and other substances are laid down or settled in a new location.

Slowing

The reduction in speed or rate of an activity or process.

Current

A directional movement of water, which can be caused by temperature, salinity differences, wind, or tidal forces in the ocean.

Sediment

Particles or fragments of rocks, minerals, or organic materials that have been transported and deposited by wind, water, or ice.