Statement I : Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth. Statement II : The Earth rotates from west to east.
- A.Both the statements are individually true and Statement II is the correct explanation of Statement I
- B.Both the statements are individually true but Statement II is not the correct explanation of Statement I
- C.Statement I is true but Statement II is false
- D.Statement I is false but Statement II is true
Correct answer
Explanation
The correct answer is B. Both statements are true, but the direction in which the Earth spins does not explain why tides occur.
Tides are caused mainly by the Moon's pull, with the Sun adding a smaller pull; the Moon's tide-raising force is roughly twice the Sun's because it is so much closer. Water bulges on the side facing the Moon and on the far side, and as the Earth rotates once a day each place passes through two high tides and two low tides. When the Sun, Moon and Earth are in a line, at new and full moon, spring tides are highest; at the quarter phases, neap tides are lowest. Statement II, that the Earth rotates from west to east, is a true fact, but it only explains why the Sun rises in the east, not the cause of tides.
A is wrong because Statement II does not explain the rise and fall of sea level.
C is wrong because Statement II is true.
D is wrong because Statement I correctly describes tides.
Exam tip: spring tides at new and full moon; neap tides at the first and last quarter.
Practice Questions
View allWhich one of the following states of India has the largest area under dense evergreen forest cover ?
- A.Himachal Pradesh
- B.Arunachal Pradesh
- C.Karnataka
- D.Uttarakhand
Show answer
Its heavy rainfall, warm humid foothills and low population give it the largest stretch of dense evergreen forest among these states.
Read the full explanation →Consider the following statements :
1. Many of the world's largest mountain chains exist beneath the sea.
2. Some mountain chains are revealed as island arcs.
3. The mid-oceanic ridges form the longest mountain chains.
4. The mid-Atlantic ridge rises thirty-three metres above the floor of the Atlantic.
Which of the statements given above are correct ?
- A.1 and 2 only
- B.3 and 4 only
- C.1, 2 and 4 only
- D.1, 2 and 3 only
Show answer
Statement 4 is wrong: the Mid-Atlantic Ridge rises thousands of metres above the ocean floor, not thirty-three metres. The ocean floor has relief as varied as the land.
Read the full explanation →Which one of the following is the main method by which potholes are created in bedrocks by the flowing stream?
- A.Abrasion
- B.Attrition
- C.Corrosion
- D.Solifluction
Show answer
Potholes are drilled into a stream's rocky bed by pebbles and boulders that the swirling water grinds against the rock.
Read the full explanation →Consider the following statements :
1. The Great Northern Plains are formed by basins of three distinct river systems - the Indus, the Ganga and the Brahmaputra.
2. They are one of the most densely populated areas on Earth.
3. Between the Yamuna at Delhi and the Bay of Bengal, nearly 1600 km away, there is a drop of only 200 metres in elevation.
Which of the statements given above are correct?
- A.1, 2 and 3
- B.2 and 3 only
- C.1 and 2 only
- D.1 and 3 only
Show answer
All three statements correctly describe the Northern Plains of India. The Northern Plains were built from alluvium laid down by the Indus, the Ganga and the Brahmaputra and their tributaries, which together drain the Himalayas.
Read the full explanation →Which of the following types of mass movements are categorized as rapid movements?
1. Creep 2. Mudflow 3. Solifluction 4. Slump
Select the answer using the code given below.
- A.1 and 2
- B.1 and 3
- C.2 and 4
- D.3 and 4
Show answer
Mudflow and slump happen quickly enough to be seen, while creep and solifluction are slow movements noticed only over long periods.
Read the full explanation →