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Laser Safety A 0.75-mW laser emits a narrow beam of light
Chapter 25, Problem 61P(choose chapter or problem)
Laser Safety A \(0.75-m W\) laser emits a narrow beam of light that enters the eye, as shown in Figure 25–27.
(a) How much energy is absorbed by the eye in 0.2 s?
(b) The eye focuses this beam to a tiny spot on the retina, perhaps \(5.0 \mu m\) in diameter. What is the average intensity of light \(\left(i n W / c m^{2}\right)\) at this spot?
(c) Damage to the retina can occur if the average intensity of light exceeds
\(1.0 \times 10^{-2} W / c m^{2}\). By what factor has the intensity of this laser beam exceeded the safe value?
Equation Transcription:
Text Transcription:
0.75-mW
5.0 \mu m
(in W/ cm^2)
1.0 x 10^-2 W/cm^2
Questions & Answers
QUESTION:
Laser Safety A \(0.75-m W\) laser emits a narrow beam of light that enters the eye, as shown in Figure 25–27.
(a) How much energy is absorbed by the eye in 0.2 s?
(b) The eye focuses this beam to a tiny spot on the retina, perhaps \(5.0 \mu m\) in diameter. What is the average intensity of light \(\left(i n W / c m^{2}\right)\) at this spot?
(c) Damage to the retina can occur if the average intensity of light exceeds
\(1.0 \times 10^{-2} W / c m^{2}\). By what factor has the intensity of this laser beam exceeded the safe value?
Equation Transcription:
Text Transcription:
0.75-mW
5.0 \mu m
(in W/ cm^2)
1.0 x 10^-2 W/cm^2
ANSWER:
Step 1 of 3
(a) Laser beam is directly giving its entire power to the eye so energy can be represented in terms of power of laser beam and time
The energy absorbed by eye is