The resolving power of an astronomical telescope is $0.2$ seconds. If the central half portion of the objective lens is covered,the resolving power will be......$sec$

Two points separated by a distance of $0.1 \ mm$ can just be seen in a microscope when light of wavelength $6000 \ Å$ is used. If the light of wavelength $4800 \ Å$ is used,the limit of resolution will become: (in $mm$)

$A$ person is observing a bacteria through a compound microscope. For better analysis and to improve the resolving power,he should:

The value of numerical aperture of the objective lens of a microscope is $1.25$. If light of wavelength $5000\,\mathring{A}$ is used, the minimum separation between two points, to be seen as distinct, will be....$\mu m$

An electron microscope is operated at $40 \ kV$. The ratio of the resolving power of this microscope to another one which uses yellow light of wavelength $6 \times 10^{-7} \ m$ is:

Two-point white dots are $2 \,mm$ apart on a black paper. They are viewed by an eye of pupil diameter $3 \,mm$. What is the maximum distance at which these dots can be resolved by the eye (in $\,m$)? $(\lambda = 500 \,nm)$