Consider the following
- Electromagnetic radiation
- Geothermal energy
- Gravitational force
- Plate movements
- Rotation of the earth
- Revolution of the earth
Which of the above are responsible for bringing dynamic changes on the surface of the earth?
[UPSC Civil Services Exam – 2013 Prelims]
(a) 1, 2, 3 and 4 only
(b) 1, 3, 5 and 6 only
(c) 2, 4, 5 and 6 only
(d) 1, 2, 3, 4, 5 and 6
Answer: (d)
Explanation:
- Electromagnetic Radiation:
- EMR has electric and magnetic fields and travels in waves. It includes radio waves, microwaves, infrared light, visible light, ultraviolet light, x-rays, and gamma rays. Electromagnetic radiation brings dynamic changes to the Earth’s surface.
- Geothermal Energy:
- Energy from within the Earth is the main force behind endogenic geomorphic processes. It is generated by radioactivity, rotational and tidal friction, and primordial heat from the origin of the Earth. Geothermal gradients and heat flow from within induce diastrophism and volcanism in the lithosphere, causing variations in crustal thickness and strength.
- Gravitational Force:
- Gravity is a directional force that activates all downslope movements of matter and causes stresses on the Earth’s materials. Mass movements and avalanches are examples of this.
- Plate Movements:
- Plate movement results in continent building and earthquakes.
- Rotation of the Earth:
- Rotation of the Earth about its axis causes uneven heating of the Earth’s surface, leading to pressure differences and the formation of winds. Winds are associated with phenomena such as rainfall, heat budget, and ocean currents.
- Revolution of the Earth:
- The Earth rotates around the Sun in an elliptical manner. The distance between the Sun and the Earth is highest during aphelion and smallest during perihelion, creating differences in the intensity of sunlight that reaches the Earth. The Earth’s gravitational force causes tides in the ocean.
Therefore, option (d) is the correct answer.
