Question map
Not attempted Correct Incorrect ★ Bookmarked
Loading…
Q15 (NDA-I/2013) Geography › World Physical Geography › Atmospheric heat balance Answer Verified

Which of the following statements is/are true? 1. The angle of the axis in relation to the plane in which the earth revolves around the sun is not constant. 2. The amount of energy given off by the sun changes with the transparency of the atmosphere. Select the correct answer using the code given below.

Result
Your answer: —  Â·  Correct: A
Explanation

Statement 1 is true because Earth's axial tilt, or obliquity, is not constant. It varies between approximately 22.1° and 24.5° over a 41,000-year cycle known as a Milankovitch cycle [1]. Currently, the tilt is about 23.4° and is slowly decreasing. Statement 2 is false because the amount of energy given off by the sun (solar irradiance) is an intrinsic property of the sun's activity, such as sunspot cycles, and is measured as the solar constant at the top of the atmosphere. While the transparency of the atmosphere (affected by clouds, dust, and aerosols) significantly influences the amount of insolation that reaches the Earth's surface, it does not change the amount of energy actually 'given off' by the sun itself [2]. Therefore, only the first statement regarding the variation of the axial tilt is correct.

Sources

  1. [1] https://www.sciencedirect.com/topics/earth-and-planetary-sciences/milankovitch-cycle
  2. [2] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 8: Solar Radiation, Heat Balance and Temperature > Variability of Insolation at the Surface of the Earth > p. 67
How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
50%
got it right
✓ Thank you! We'll review this.

SIMILAR QUESTIONS

NDA-II · 2009 · Q34 Relevance score: 3.31

Consider the following statements : 1. The earth’s rotation axis is not at 90° to its orbital plane, 2. The earth’s rotation axis is inclined at 23.5°. Which of the statements given above is/are correct?

NDA-I · 2011 · Q99 Relevance score: 1.08

Statement I : In the northern hemisphere the ocean currents flowing from equator towards the north pole and from pole towards the equator are deflected to their right Statement II : This happens due to rotation of the Earth on the axis from west to east

NDA-I · 2010 · Q5 Relevance score: 0.98

Statement I : Winds are deflected to their right in the northern hemisphere and to their left in the southern hemisphere. Statement II : The Earth’s axis is inclined.

CDS-II · 2010 · Q95 Relevance score: 0.77

Which of the following statements is/are correct with respect to the Chilean , Earthquake (February 2010) ? 1. Scientists estimated that the Earth’s axis of rotation had moved by 3 inches due to the earthquake. 2. Santa Maria island off the coast near Concepcion, Chile’s second largest city, may have been raised by 2 metres. Select the correct answer using the code given below:

IAS · 2025 · Q33 Relevance score: 0.52

Consider the following statements : Statement I : Scientific studies suggest that a shift is taking place in the Earth's rotation and axis. Statement II : Solar flares and associated coronal mass ejections bombarded the Earth's outermost atmosphere with tremendous amount of energy. Statement III : As the Earth's polar ice melts, the water tends to move towards the equator. Which one of the following is correct in respect of the above statements?