Question

(a) What magnification is produced by a 0.150 cm focal length microscope objective that is 0.165 cm from the object being viewed?
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(b) What is the overall magnification if an eyepiece that produces a magnification of 8.30? is used?
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Answer 1

a) Magnification = m₀(magnification of objective lens)*m_e(magnification of eyepiece) = {(v₀/f₀)-1}*(1+d/f_e),

where v₀=image distance,

f₀ = focal length of objective piece,

d = least distant vision i.e. 25cm,

f_e = focal length of eyepiece,

1/v - 1/u = 1/f or 1/v = 1/f + 1/u

so 1/v = 1/0.150 + 1/(-0.165) (u is taken as negative according to sign convention)

v₀ = 1.65cm, f₀ = 0.150cm

magnification of objective lens (m₀) = v₀/f₀ -1 or

m₀ = 10

b) overall magnification = m₀*m_e or

10*8.30

=83