Three thin lenses are combined by placing them in contact with each other to get more magnification in an optical instrement. Each lens has a focal length of 3 cm. If the least distance of distinct vision is taken as 25 cm, the total magnification of the lens combination in normal adjustment is

Options

A. 9
B. 26
C. 300
D. 3

Answer

B

Explanation

The total magnification of the lens is given by,
`M=1 + D/f`
`f= 1/f_(1) + 1/f_(2) + 1/f_(3) = 1/3+ 1/3+1/3= 1cm`
` implies M=1+ 25/1= 26`