Question

The objective lens in a microscope with a 17.0 cm long tube has a magnification of -50.0 and the eyepiece has a magnification of 20.0. (a) What is the focal length of the objective? (b) What is the focal length of the eyepiece?

Answer 1

(a) 0.34 cm

(b) 1.32 cm

Step-by-step explanation:

Given that,
`m_(o)=-50`

`m_(e)=20 cm`

And the length of objective lens in a microscope

`L=17`

And we have d of the eyepiece is 25 cm.

(a) Focal length of the objective is,

`f_(o)=-(L)/(m_(o) )\\  f_(o)=-(17)/(-50) \\f_(o)=0.34 cm`

Therefore, objective lens's focal length is 0.34 cm.

(b) Focal length of an eyepiece,

`m_(e)=(1+(d)/(f_(e) ))\\  20=(1+(25)/(f_(e) )\\ f_(e)=(25)/(19)cm\\ f_(e)=1.32cm`

Therefore, eyepiece's focal length is 1.32 cm.