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Tanya
16 days ago
15

Lasers are classified according to the eye-damage danger they pose. Class 2 lasers, including many laser pointers, produce visib

le light with no greater than 1.0 mW total power. They're relatively safe because the eye's blink reflex limits exposure time to 250 ms.
Requried:
a. Find the intensity of a 1-mW class 2 laser with beam diameter 2.0 mm .
b. Find the total energy delivered before the blink reflex shuts the eye.
c. Find the peak electric field in the laser beam.
Physics
1 answer:
kicyunya [3.2K]16 days ago
6 0

Response:

a) 318.2 W/m^2

b) 2.5 x 10^-4 J

c) 1.55 x 10^-8 v/m

Reasoning:

The laser power P = 1 mW = 1 x 10^-3 W

duration t = 250 ms = 250 x 10^-3 s

Taking a beam diameter of 2 mm = 2 x 10^-3 m

therefore

the beam's cross-sectional area A = \pi d^{2} /4 = (3.142 x (2*10^{-3} )^{2})/4

A = 3.142 x 10^-6 m^2

a) The intensity I = P/A

where P refers to the laser's power

and A represents the beam's cross-sectional area

I = ( 1 x 10^-3)/(3.142 x 10^-6) = 318.2 W/m^2

b) The total energy delivered E =Pt

where P is the beam's power

and t is the exposure duration

E = 1 x 10^-3 x 250 x 10^-3 = 2.5 x 10^-4 J

c) The peak electric field can be computed as

E = \sqrt{2I/ce_{0} }

where I signifies the beam's intensity

and E is the electric field

c is the speed of light = 3 x 10^8 m/s

e_{0} = 8.85 x 10^9 m kg s^-2 A^-2

E = \sqrt{2*318.2/3*10^8*8.85*10^9} = 1.55 x 10^-8 v/m

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19 days ago
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Yuliya22 [3333]

Response:

The acceleration of car 2 is four times that of car 1.

Rationale:

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The equivalent distance in kilometers is 4012 ×10^{-6} km.

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4012 mm = 4012 ×10^{-6} km.

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A sculptor has asked you to help electroplate gold onto a brass statue. You know that the charge carriers in the ionic solution
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Answer:

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