Question

Hubble telescope uses light of wavelength $550\text{nm}$ through a $2.44\text{m}$ aperture. The height of Hubble telescope above the surface of Earth is given to be $600\text{km}.$ Find the least distance between two objects on the surface of Earth to be visible to the telescope sufficiently resolved.

• A. $10\text{cm}$
• B. $4\text{cm}$
• C. $8.7\text{cm}$
• D. $16.5\text{cm}$

Answer 1

The correct option is D $16.5\text{cm}$

The minimum distance of separation to resolve two objects by telescope is given by, $S=\left(\frac{1.22\lambda }{d}\right)D$

Substituting the data given in the question,

$S=1.22\times \frac{550\times {10}^{-9}}{2.44}\times 600\times {10}^3=16.5\times {10}^{-2}\text{m}=16.5\text{cm}$

Hence, option $\left(d\right)$ is correct.