How Much Energy Does a 3.5 mW He-Ne Laser Beam Carry Over 1 Meter?

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SUMMARY

The energy carried by a 3.5 mW He-Ne laser beam over a distance of 1 meter can be calculated using the formula for energy in terms of power and time. Given that power (P) is 3.5 mW or 0.0035 W, the energy (E) can be determined by multiplying power by time. Since light travels 1 meter in approximately 3.33 nanoseconds, the energy carried over this distance is 0.0035 W multiplied by the time taken to travel 1 meter, resulting in an energy of approximately 1.17 microjoules.

PREREQUISITES
  • Understanding of basic physics concepts such as energy, power, and time.
  • Knowledge of the relationship between watts and joules (1 W = 1 J/s).
  • Familiarity with the speed of light and its implications in calculations.
  • Ability to perform unit conversions, specifically from milliwatts to watts.
NEXT STEPS
  • Study the relationship between energy, power, and time in physics.
  • Learn about the speed of light and its applications in various calculations.
  • Explore the concept of intensity in laser beams and how it relates to energy distribution.
  • Investigate the properties of He-Ne lasers and their applications in scientific research.
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Students in physics, engineers working with laser technology, and anyone interested in understanding energy calculations in optical systems.

sgoeke
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Homework Statement


Determine the amount of energy carried in 1 m of a 3.5 mW He-Ne laser beam if the cross-sectional area of the beam is 5x10^-6 m^2.


Homework Equations


J/s = Watt


The Attempt at a Solution


I converted the mW to W. I feel like I should put .0035W over 5x10^-6 m^2 to get intensity. But I don't know where intensity comes into this problem or where the other 1 m comes in.
 
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sgoeke said:

Homework Statement


Determine the amount of energy carried in 1 m of a 3.5 mW He-Ne laser beam if the cross-sectional area of the beam is 5x10^-6 m^2.


Homework Equations


J/s = Watt


The Attempt at a Solution


I converted the mW to W. I feel like I should put .0035W over 5x10^-6 m^2 to get intensity. But I don't know where intensity comes into this problem or where the other 1 m comes in.

What is energy in terms of power and time? How long does it take light to travel 1 meter?

And remember that sometimes in problems, you may not need everything that you are given...
 

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