Consider the following:
- 1.Electromagnetic radiation
- 2.Geothermal energy
- 3.Gravitational force
- 4.Plate movements
- 5.Rotation of the earth
- 6.Revolution of the earth
Which of the above are responsible for bringing dynamic changes on the surface of the earth?
Answer & explanation
Answer: (d) 1, 2, 3, 4, 5 and 6
All six are responsible, so the answer is (d). Surface changes come from internal (endogenic) and external (exogenic) forces. Geothermal energy and plate movements drive the internal ones. Solar radiation and gravity drive the external ones. Earth's rotation and revolution add to both.
- ✓ 1. Electromagnetic radiation, mainly from the sun, is the ultimate energy source for exogenic processes such as weathering and erosion. The sun's heating sets up the atmospheric conditions that drive them.
- ✓ 2. Geothermal gradients and heat flow from within the earth induce diastrophism and volcanism in the lithosphere. These are the endogenic processes.
- ✓ 3. Gravity acts on all earth materials on a slope and pulls them downslope. This causes mass movements and powers the work of running water, glaciers and other agents.
- ✓ 4. Plate movements are tectonic (diastrophic) movements. They build mountains, rifts, volcanoes and earthquake zones. They also create the slopes on which exogenic processes act.
- ✓ 5. Rotation causes the day–night temperature cycle, the Coriolis deflection of winds and ocean currents, and the daily rise and fall of tides, all of which work on the surface. Rotational and tidal friction is also one of the sources of the earth's internal energy.
- ✓ 6. Revolution, together with the tilt of the axis, produces the seasons. Seasonal changes in temperature and rainfall alter the rates of weathering, erosion and deposition.
Remember · Endogenic forces (geothermal heat, plate movements) build the surface. Exogenic forces (solar energy, gravity) wear it down. Earth's rotation and revolution also modify it.
📘 Read it in NCERT: Class 11 Fundamentals of Physical Geography, Ch 5 (practise this chapter) · Class 11 Fundamentals of Physical Geography, Ch 5 (practise this chapter) · Class 11 Fundamentals of Physical Geography, Ch 5 (practise this chapter)
Sources
- NCERT Class 11 · Fundamentals of Physical Geography, Chapter 5 “This energy due to geothermal gradients and heat flow from within induces diastrophism and volcanism in the lithosphere.”
- NCERT Class 11 · Fundamentals of Physical Geography, Chapter 5 “The exogenic processes derive their energy from atmosphere determined by the ultimate energy from the sun and also the gradients created by tectonic factors.”
- NCERT Class 11 · Fundamentals of Physical Geography, Chapter 5 “Gravitational force acts upon all earth materials having a sloping surface and tend to produce movement of matter in down slope direction.”
Question: UPSC Civil Services (Preliminary) 2013, General Studies Paper I. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·
