Question

Two points separated by $0.05\, mm$ can just be inspected in a microscope when light of wavelength $6000 \,\mathring{A}$ is used. If light of wavelength $3000 \,\mathring{A}$ is used then the limit of resolution becomes

• A. 0.05 mm
• B. 0.025 mm
• C. 0.1 mm
• D. 0.15 mm

Answer 1

Answer: (B)

Resolving power of a microscope is the shorter distance between two seperate point in a microscope's field of view that can be seen directly.
Resolving power $\propto \frac{\lambda}{2 a}$
($a = $ aperture)
$\frac{d_{1}}{d_{2}}=\frac{\lambda_{1}}{\lambda_{2}} $
$\Rightarrow \frac{0.05}{d_{2}}=\frac{6000}{3000}$
$ \Rightarrow 0.025 \,mm$