Answer:
power = 20X
focal length = L/ 20
Explanation:
Given data
magnification = 200X
eyepiece = 10X
to find out
power objective is needed and focal length of the objective
solution
we know magnification of microscope M is the product of ( m1 ) magnifying power of object and ( m2 )magnifying power of eyes
that is M = M1 × M2
so M1 = M / M2
put value M = 200 and M2 = 10
M1 = 200/10 = 20
so here power = 20X
and
now we calculate focal length by this formula
M1 = ( L/focal length ) M2
here L is length of tube put all value
200 =( L/focal length ) 10
focal length = L/ 20