Civil Engineering - UPSC Civil Service Exam Questions - Discussion

19. 

A sailor, standing on the deck of a ship, just sees the light beam from a lighthouse on the shore. If the height of the sailor's eye and of the light beam at the lighthouse, above the sea level, are 9 m and 25 m respectively, what is the distance between the sailor and the lighthouse ?

[A]. 29.8 km
[B]. 31.1 km
[C]. 31.9 km
[D]. 33.2 km

Answer: Option B

Explanation:

No answer description available for this question.

Chhaya said: (May 31, 2017)  
Here, (25/0.0675)^0.5 + (9/0.0675)^0.5 = 31.1.

Raj said: (Jun 25, 2017)  
Will you please explain in detail?

Ravi said: (Jul 9, 2017)  
Explain me, please.

Shreya said: (Nov 4, 2017)  
D = sqrt(H/0.06735).

D = sqrt(25/0.06735) + sqrt(9/0.06735) = 30.82.

Phani said: (Apr 28, 2018)  
D = 3.855(25^0.5 + 9^0.5),
= 30.85 ~~ 31.1.

Ashish K. said: (Jan 1, 2019)  
H=.0675d2.

Hence d= H/0.0675.
D=d1+d2,
= 25/.0675 + 9/0.0675.
31.1km.

Poonam said: (Aug 13, 2021)  
Use formula Height = 0.0673 x d^2.
Here H1 abd H2 are given 25 and 9 respectively,
Find d1 and d2.
Then D = d1+ d2.

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