Solve it n please don't send too small pics of answer.
Q.10. A micro-organism, when viewed under a compound microscope with an objective lens of 40 X and an eye piece of 10 X magnification measured 4000 $\mu$ in length. The same micro-organism when observed under a dissection microscope with a lens of 10 X magnification, would measure ............
1) 100 $\mu$
2) 40 $\mu$
3) 400 $\mu$
4) 10 $\mu$