The smallest object detail that can be resolved with a microscope using light of wavelength `600 nm` is `3.5 xx 10^(-5) cm`. Find N.A of objective when used dry and when immersed in an oil of `mu = 1.6`.

Answer

`0.86 ; 1.376`

Explanation

Here, `lambda = 600 nm = 6 xx 10^(-7)m`,
`d = 3.5 xx 10^(-5) cm = 3.5 xx 10^(-7) m`
When objective is used dry,
`N.A = (lambda)/(2d) = (6 xx 10^(-7))/(2 xx 3.5 xx 10^(-7)) = 0.86`
When objective is immersed in an oil of `mu = 1.6`.
`N.A = mu xx (dry)N.A`
`= 1.6 xx 0.86 = 1.376`