An object is seen thorugh a simple microscope of focal length 12 c. Find the angular mgnification produced if the image is formed at the near pointofhe eye which is 25 cm away from it.

Options

A. 6.08
B. 3.08
C. 9.03
D. 5.09

Answer

B

Explanation

(b) Given focal length of simole microscope=12cm
Near point D=25cm
From lens formula `(1)/(v)-(1)/(u)=(1)/(f) Rightarrow (1)/(25)-(1)/(u)=(1)/(-12)`
`Rightarrow (1)/(u)=(1)/(12)+(1)/(25)`
`Rightarrow (1)/(u)=(25+12)/(300)=(37)/(300)`
`therefore u=(300)/(37)`
Magnification `m=(v)/(u)` `(25)/((300)/(37))=(25xx37)/(300) Rightarrow m=3.08`