Answer:
[tex]1.6 \times 10^{-8}[/tex]
Explanation:
The whole sky is considered as a sphere called as Celestial Sphere.
Total no. of stars visible to the naked eye in the whole sky = 9000
Area of the whole sky in degrees = 41200 square degrees
No. of stars in 1 square degree = [tex]\frac{9000}{41200}[/tex] = 0.218
Also 1 degree = 60 arcminutes
1 arcminute = 60 arcseconds
Thus, 1 degree = 3600 arcseconds
Thus, No. of stars visible in per square arcsecond = [tex]\frac{0.218}{3600\times 3600} = 1.6 \times 10^{-8}[/tex]
