Question

Light of wavelength 589 nm is used to view an object under a microscope. The objective lens of the microscope is the lens that gathers light from the object being observed and focuses the light rays in order to form an image of the object. It acts as the aperture of the system, determining its resolution. In this case, the objective lens is circular, of diameter 0.95 cm. Assuming that the resolution of the microscope depends solely on the diffractive effect of the entrance aperture (i.e. the microscope is diffraction limited), answer the following questions. (i) What is the angular resolution of the microscope for 589 nm light? (2 marks) (ii) The visible spectrum extends approximately from 390 nm to 700 nm. If it were possible to use any wavelength in this range, what would be the best (smallest) angular resolution that could be achieved? (1 mark) (iii) Assume that a fluid of refractive index n=1.50 now fills the space between the object and the objective lens. What effect does this have on the angular resolution when 589 nm light is used?

Answer 1

The Answers are

i) A=4.33*10^(-3)

ii) The smallest Resolution which can be achieved is of 390 nm

iii) The Resolution get Smaller