Two identically built microscopes are being used to characterize sub-micron features with two different laser sources. The first microscope uses a laser at 632 nm (red), and the smallest feature it can measure is 500 nm. If the second microscope uses a laser at 543 nm (green), what is the smallest feature it can measure

Respuesta :

Answer:

[tex]r_2\approx430\ nm[/tex]

Explanation:

Given:

wavelength used by the first microscope, [tex]\lambda_1=632\times 10^{-9}\ m[/tex]

resolving power of the first microscope, [tex]r_1=500\times 10^{-9}\ m[/tex]

wavelength used by the second microscope, [tex]\lambda_2=543\times 10^{-9}\ m[/tex]

For the microscopes the resolving power is given as:

[tex]r=1.22\times \frac{\lambda}{a}[/tex]

where:

[tex]\lambda =[/tex] wavelength of the laser source used

[tex]a=[/tex] numerical aperture of the microscope

[tex]r=[/tex] smallest feature that can be distinguished using the optical device

For the first microscope:

[tex]r_1=1.22\times \frac{\lambda_1}{a_1}[/tex]

[tex]500\times 10^{-9}=1.22\times\frac{632\times 10^{-9}}{a_1}[/tex]

[tex]a_1=1.54208[/tex]

Since both the optical device are identically built we will have:

[tex]a_2=a_1=1.54208[/tex]

Now for the second optical device:

[tex]r_2=1.22\times \frac{\lambda_2}{a_2}[/tex]

[tex]r_2=1.22\times \frac{543\times 10^{-9}}{1.54208}[/tex]

[tex]r_2\approx430\ nm[/tex]