Questions and answers for exam Preparation

MCQs

Total Questions : 242 | Page 4 of 25 pages

Question 31. Assertion A : Basin walls have to be of much grater height than dock walls.Reason R : Tidal basins are subject to fluctuations of levels due to tidal variations.Select your answer based on the coding system given below:

Both A and R are true and R is the correct explanation of A.
Both A and R are true but R is not correct explanation of A.
A is true but R is false.
A is false but R is true.

Discuss Question

Answer: Option A. -> Both A and R are true and R is the correct explanation of A.

Question 32. Assertion A : Depth and width required at the entrance to a harbour are more than those required in the channel.Reason R : The entrance to a harbour is usually more exposed to waves as compared to the harbour itself.Select your answer based on the coding system given below:

Both A and R are true and R is the correct explanation of A.
Both A and R are true but R is not the correct explanation of A.
A is true but R is false.
A is false but R is true.

Discuss Question

Answer: Option A. -> Both A and R are true and R is the correct explanation of A.

Question 33. If the maximum spring rise is 2 m and height of the waves expected is 4 m , then the breakwater height above the datum will be

2.5 m
4 m
5 m
7 m

Discuss Question

Answer: Option D. -> 7 m

Question 34. As per Stevenson’s empirical formula, the approximate value of the height of the wave in metres is given by (where F is the fetch in km.)

0.34 VF
0.5 VF
1.5 VF
3.4 VF

Discuss Question

Answer: Option A. -> 0.34 VF

Question 35. At a given port, the fetch is 400 nautical miles, the maximum height of storm wave will be

2.073 m
8.169 m
9.144 m
6.8 m

Discuss Question

Answer: Option C. -> 9.144 m

Question 36. If ‘Hs’ is the significant wave height, then the average wave height and highest wave height respectively are given by

0.6 Hs and 1.67 Hs
0.6 Hs and 1.87 Hs
1.27 Hs and 1.87 Hs
1.27 Hs and 1.67 Hs

Discuss Question

Answer: Option B. -> 0.6 Hs and 1.87 Hs

Question 37. The difference in height between highest high water and lowest low water is called

Mean range
Maximum range
Maximum rise
Mean rise

Discuss Question

Answer: Option B. -> Maximum range

Question 38.

If h and h₁
are the heights of a light house and the observer in a ship in metres
above M S L then the horizontal distance from the ship to the light
house in kilometres is

`3.86 (sqrt(h) + sqrt(h_1))`
`3.86 (sqrt(h) - sqrt(h_1))`
`3.86 (sqrt(h) xx sqrt(h_1))`
`3.86 pi (sqrt(h) + sqrt(h_1))`

Discuss Question

Answer: Option A. -> `3.86 (sqrt(h) + sqrt(h_1))`

Question 39.

The horizontal angles from the boat between A and B and B and C, the stations on the shore are respectively `theta_1 and theta_2`. The distances AB = L₁ and BC = L₂. For calculating the angle`alpha_2` at C between the boat and station B is obtained by using the following formula: where (`beta` is horizontal angle between A and C at B).

`(sin alpha_1)/(sin alpha_2) = (L_2 sin theta_1)/(L_1 sin theta_2) = K `
`alpha_t tan alpha_2 = 360^circ - ( theta_1 + theta_2 + beta) = phi`
`tan alpha_2 = (sin phi)/(K + cos phi)`
all the above.

Discuss Question

Answer: Option D. -> all the above.

Question 40.

P and Q are two stations on the shore line at distance d. If the angle between Q and the boat O and P is a and the angle between P and Q at boat O is `beta`, the x and y. Coordinate along PQ and perpendicular to PQ from O are :

` x = (d tan beta)/(tan alpha + tan beta) ; Y = (d tan alpha tan beta)/(tan alpha + tan beta)`
` x = (d tan beta)/(tan alpha - tan beta) ; Y = (d tan alpha tan beta)/(tan alpha - tan beta)`
` x = (d tan alpha tan beta )/(tan alpha + tan beta) ; Y = (d tan beta )/(tan alpha + tan beta)`
none of the above.

Discuss Question

Answer: Option A. -> ` x = (d tan beta)/(tan alpha + tan beta) ; Y = (d tan alpha tan beta)/(tan alpha + tan beta)`