Question

The least resolvable angle by a telescope using objective of aperture 5 m is nearly ($\lambda =4000A^{\circ }$)

• A. $\frac{1}{{50}^{\circ }}$
• B. $\frac{1}{50}$ minute
• C. $\frac{1}{50}$sec
• D. $\frac{1}{500}$sec

Answer 1

The correct option is C $\frac{1}{50}$sec

$R=\frac{9}{1.22\lambda }$
$\frac{1}{\Delta \theta }=\frac{5}{1.22\times 4000\times {10}^{-10}}$
$\Delta \theta =\frac{1}{50}sec$