Question

An object is placed at a distance u from a simple microscope of focal length f. The angular magnification obtained depends

Options

• on f but not on u

• on u but not on f

• on f as well as u

• neither on f nor on u

Answer 1

 on f as well as u

​The angular magnification is the ratio of the angle subtended by the image to the angle subtended by the object on an unaided eye.
In a simple microscope,

m=`(h/u)/(h/D)`

Here,

u = Object distance from the lens

D = Image distance from the lens

h = Height of the object

In normal adjustment, the object is placed at a distamce equal to  ​focal length(f)  from the lens and then magnification is given by m = D/f.
For u < f, m = D/f +1.