A light house of 120 m height is just visible above the

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A light house of 120 m height is just visible above the horizon from a ship. The correct distance (m) between the ship and the light house considering combined correction for curvature and refraction, is

1. 39.098
2. 422.26
3. 39.98
4. 42.226

Correct Option: D

h =	D²	(1 - 2m)
	2R

h₁ = 0.0673D²
∴ D = 3.856 √h
D = 3.856 √120 = 42.23 km.