Question

Two stars distant two light years are just resolved by a telescope. The diameter of the telescope lens is 0.25 m. If the wavelength of light used in $5000A^0,$ then the minimum distance between the stars is

• A. $1.22\times {10}^{11}m$
• B. $2.44\times {10}^{11}m$
• C. $3.66\times {10}^{10}m$
• D. $4.88\times {10}^{10}m$

Answer 1

The correct option is A $1.22\times {10}^{11}m$

$\Delta \theta =\frac{1.22\times 5000\times {10}^{-10}}{\left(.25\right)}$
$\Delta \theta =2.44\times {10}^{-6}$