Chapter 25 - Vision and Optical Instruments - Learning Path Questions and Exercises - Exercises - Page 873: 57

$4.1\times10^{16}km$

$D=300m$ $wavelength=4m$ $r=2.5\times10^{18}km$ $\theta_{min}=\frac{1.22\times wavelength}{D}=\frac{1.22\times4}{300}=0.01626rad$ Since, $s=r\theta_{min}$ $s=2.5\times10^{18}\times 0.01626=4.1\times10^{16}km$