Question

In a compound microscope, the focal lengths of two lenses are 1.5 cm and 6.25 cm. If an object placed at 2 cm from objective and the final image is formed at 25 from eye lens, the distance between the two lenses is

• A. $6.00cm$
• B. $7.75cm$
• C. $9.25cm$
• D. $11.0cm$

Answer 1

Answer: (D)

$11.0cm$

Answer : D

Solution : $L=u_0+u_e=\frac{u_0{f}_0}{(u_0-f_0)}+\frac{f_{e}D}{f_e+D}$

$\Rightarrow L=\frac{2\times 1.5}{(2-1.5)}+\frac{6.25\times 25}{(6.25+25)}=11cm$