The periodic rise and fall of ocean water in response to gravitational forces is called
- A.Current
- B.Waves
- C.Tides
- D.Tsunami
Correct answer
Explanation
The correct answer is C, Tides. Tides are the regular rise and fall of sea level caused mainly by the gravitational pull of the Moon, and to a lesser extent the Sun, on the Earth.
Most coasts have two high tides and two low tides in a little over 24 hours, about 24 hours and 50 minutes. When the Sun, Moon and Earth are in a line, at new moon and full moon, their pulls add up and give spring tides, the highest high tides. When the Sun and Moon are at right angles to the Earth, at the first and last quarters, the pulls partly cancel and give neap tides. Tidal energy is harnessed in places like the Gulf of Khambhat.
A is wrong because ocean currents are steady flows of water driven by winds, temperature and salinity, not periodic rises.
B is wrong because waves are surface movements caused mainly by wind.
D is wrong because a tsunami is a huge wave set off by an undersea earthquake, landslide or volcanic eruption.
Exam tip: spring tides at new and full moon, neap tides at the quarter moons; the Moon's pull matters more than the Sun's.
Practice Questions
View allWhich one of the following Indian cities is not located on a river bank ?
- A.Agra
- B.Bhagalpur
- C.Bhopal
- D.Kanpur
Show answer
Bhopal, the capital of Madhya Pradesh, is not built on a river bank; it is known instead as the City of Lakes.
Read the full explanation →Milpa and Ladang are different names for
- A.shifting cultivation.
- B.mixed farming.
- C.truck farming.
- D.plantation agriculture.
Show answer
Milpa is the name for shifting cultivation in Mexico and Central America, and Ladang is its name in Malaysia and Indonesia.
Read the full explanation →The Tetrahedral Hypothesis of the origin of continents and ocean basin was proposed by
- A.F.B. Taylor
- B.Lowthian Green
- C.Alfred Wegener
- D.W.M. Davis
Show answer
The English geologist William Lowthian Green put forward the Tetrahedral Hypothesis in 1875 to explain how continents and ocean basins are arranged.
Read the full explanation →Which one of the following statements is correct?
For the purpose of Census 2011
- A.a person aged seven and above who can both read and write with understanding in any language is treated as a literate
- B.a person aged eight and above who can both read and write with understanding in any language is treated as a literate
- C.a person aged nine and above who can both read and write with understanding in any language is treated as a literate
- D.a person aged ten and above who can both read and write with understanding in any language is treated as a literate
Show answer
In Census 2011, a person aged seven and above who could both read and write with understanding in any language was counted as literate.
Read the full explanation →Which one of the following Indian States has no international boundary ?
- A.Bihar
- B.Chhattisgarh
- C.Uttarakhand
- D.Meghalaya
Show answer
Chhattisgarh lies in the heart of the country and is surrounded only by other Indian States. Chhattisgarh was carved out of Madhya Pradesh in November 2000.
Read the full explanation →