Helium-neon lasers are used in engineering laboratories, robot vision systems, and even in the barcode readers on supermarket checkout counters. A certain laser has a power output of 3 mW and produces light of wavelength λ = 632.8 nm. The lowercase Greek character lambda (λ) is a conventional symbol used for wavelength; Appendix A summarizes the names and symbols of other Greek letters.

(a) Convert the power rating to horsepower.

(b) Convert the wavelength to inches.

Solution:

The power dimension $m w$,

The Conversion factors for power and Length are $1 \mathrm{kw}=1.34 \mathrm{hp}$ $1 \mathrm{~m}=39.37$

$ 1 m=39.37 \text {. } \\ $

Solution :-

(a) we first Convert the power's sI prifix, The laser produces $3 \times 10^{-3} \mathrm{w}=3 \times 10^{-6} \mathrm{kw}$.

$ \begin{aligned}\\ P &=\left(3 \times 10^{-6} \mathrm{kw}\right)\left(2.34 z \frac{h p}{\mathrm{kw}}\right) \\\\ &\left.=4,023 \times 10^{-6} / \mathrm{kw}\right)\left(\frac{\mathrm{hp}}{\mathrm{kw}}\right) \\\\ P &=4,023 \times 10^{-6} \mathrm{hp} \\ \end{aligned} \\ $

(b) The Laser's wavelength is $632.8 \times 10^{-9} \mathrm{~m}=6.328 \times 10^{-7} \mathrm{~m}$, and the length Conversion becomes.

$ \begin{aligned}\\ \lambda &=\left(6.328 \times 10^{-7} \mathrm{~m}\right)\left(39.37 \frac{\mathrm{im}}{\mathrm{m}}\right) \\\\ &\left.=2.491 \times 10^{-5} \mathrm{~m}\right)\left(\frac{\mathrm{In} .}{\mathrm{m}}\right) \\\\ &=2.491 \times 10^{-5} \mathrm{in} \\ \end{aligned}\\ $

Discussion:-

So, larger than the Jaser's power and wavelength, they are not veey Convenient for describing its char.

$ \begin{aligned}\\ &p=4,023 \times 10^{-6} \mathrm{hp} . \\\\ &x=2.491 \times 10^{-5} \mathrm{in} .\\ \end{aligned}\\ $