Optical Instruments: Practice Problem & Solution

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Optical Instruments. Understanding the underlying formula is key to arriving at the correct answer below:

The magnifying power of a microscope is inversely proportional to the focal length of its objective ($M \propto 1/f_o$). The magnifying power of a telescope is directly proportional to the focal length of its objective ($M = f_o/f_e$). Therefore, increasing $f_o$ decreases microscope magnification and increases telescope magnification.