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Home » IES Prelims » Natural Phenomena, Tides, Wind & Waves – IES PYQ

Natural Phenomena, Tide, Wind & Waves – IES PYQ

      

1. The phenomenon of movement and deposition of sand in a zig-zag style due to drifting of sand in the vicinity of coast is called _____ .

[IES 2000]

  1. Sedimentation
  2. Beach drift
  3. Trough action
  4. Littoral drift
Answer: Option D
Explanation:
The waves near the shore line are induced due to the prevailing winds. These waves tend to stir up and move the lighter suspended sand particles in a zig-zag line. This complex movement and deposition of sand in the proximity of the shore is known as littoral drift.

2.  The lowest tide which occurs in half lunar month is called _____ .

[IES 2000]

  1. Neap tide
  2. Lunar tide
  3. Tidal bore
  4. Spring tide
Answer: Option D
Explanation:

  • Spring tides occur at full moon or rather a day or two after. Spring tides have higher high tides and lower low tides.
  • Neap tides occur during the first and third quarter moon, when the moon is half full. Neap tides have lower high tides and higher low tides.

3.  In deep water waves, individual particles _____ .

[IES 2001]

  1. Are translated and rotated in a vertical plane about horizontal axis.
  2. Are not translated, but they rotate in a vertical plane about a horizontal axis.
  3. Do not rotate in a vertical plane about a horizontal axis.
  4. Are translated
Answer: Option B
Explanation:
In deep water waves, the individual water particles move in a circular orbit in a vertical plane. But, the particles do not move towards the shore. Hence, the individual particles undergo rotation but not translation.
Note: View the motion of individual particles in deep water waves

4.  What is the wave velocity for a uniform train of wave beyond the storm centre for a wave length of 20 m in 14 m deep water ?

[IES 2007]

  1. 11.2 m/s
  2. 4.5 m/s
  3. 9 m/s
  4. 5.5 m/s
Answer: Option D
Explanation:

Water depth (d)

Wave length (l)

=

14

20

= 0.7 > 0.5

Hence, the water is deep.
In deep water, velocity, v = √  gl/2π  = √  (9.81 x 20)/2π  = 5.58 m/s
Here, the closest option is 5.5 m/s.

5.  Zigzag deposition and movement of sand on sea beach is called _____ .

[IES 2010]

  1. Beach drift
  2. Trough action
  3. Sedimentation
  4. Littoral drift
Answer: Option D
Explanation:
The waves near the shore line are induced due to the prevailing winds. These waves tend to stir up and move the lighter suspended sand particles in a zig-zag line. This complex movement and deposition of sand in the proximity of the shore is known as littoral drift.

6.  In the offshore region at a particular harbour facility, an oscillatory wave train approaches with wavelength of 80 m where the mean sea depth is 30 m. What would be the velocity of the individual waves ?

[IES 2018]

  1. 16.05 m/s
  2. 15.15 m/s
  3. 14.05 m/s
  4. 17.15 m/s
Answer: Option D
Explanation:

Water depth (d)

Wave length (l)

=

30

80

= 0.375 < 0.5

Hence, the water is shallow.
In shallow water, velocity, v = √  gd   = √  9.81 x 30 = 17.15 m/s

7.  For proper planning of harbours, oscillatory waves in the relevant off-shore region must be taken into account. If the sea depth is 30 m and an oscillatory waves train is observed to have wavelength of 50 m, what would be the velocity of the individual waves ?

[IES 2018]

  1. 9.21 m/s
  2. 9.08 m/s
  3. 8.83 m/s
  4. 9.43 m/s
Answer: Option C
Explanation:

Water depth (d)

Wave length (l)

=

30

50

= 0.6 > 0.5

Hence, the water is deep.
In deep water, velocity, v = √  gl/2π  = √  (9.81 x 50)/2π  = 8.83 m/s

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