Optical Instruments: Practice Problem & Solution

Solution Explained:

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:

For an astronomical telescope in normal adjustment, angular magnification $M = \frac{f_o}{f_e} = 10$, meaning $f_o = 10f_e$. The tube length is $L = f_o + f_e = 44 cm$. Substituting $f_o$, we get $11f_e = 44$, so $f_e = 4 cm$. Therefore, $f_o = 10 \times 4 = 40 cm$.