A compound microscope consists of an objective lens of focal length 1 cm and an eye piece of focal length 5 cm with a separation of 10 cm. The…

A compound microscope consists of an objective lens of focal length $\displaystyle 1$ cm and an eye piece of focal length $\displaystyle 5$ cm with a separation of $\displaystyle 10$ cm.The distance between an object and the objective lens, at which the strain on the eye is minimum is $\displaystyle \frac{\mathrm{n}}{40} \mathrm{~cm}$. The value of n is \_\_\_\_.