All questions of The Earth and The Universe for BPSC (Bihar) Exam

Explanation of the Correct Answer
Both statements provided relate to the effects of the Earth's axial tilt on the solar altitude and the resulting variations in day length, particularly during the solstices.
Statement-I Analysis
- Correctness: Statement-I is accurate.
- Reason: During the Summer Solstice, which occurs around June 21st, the Northern Hemisphere is tilted towards the Sun at its maximum angle of 23.5 degrees.
- Effect: This tilt increases the Sun's altitude in the sky, leading to longer daylight hours, as the Sun's rays strike the Earth more directly and for extended periods.
Statement-II Analysis
- Correctness: Statement-II is also true.
- Explanation: In regions between the Arctic Circle and the North Pole, the phenomenon known as "Midnight Sun" occurs, where the Sun remains visible for 24 hours during the summer months.
- Counterpart: Similarly, in the Antarctic region, areas between the Antarctic Circle and the South Pole experience continuous darkness for an equal duration, known as "Polar Night."
Relationship Between Statements
- Connection: Statement-II does indeed explain Statement-I by illustrating the extremes of daylight and darkness that occur due to the Earth's axial tilt during solstices.
- Conclusion: Therefore, both statements are correct, and Statement-II provides a contextual understanding of the implications of the axial tilt described in Statement-I.
Final Answer
- The correct option is (a): Both Statement-I and Statement-II are correct, and Statement-II explains Statement-I.

Understanding the Sun's Position at the Equator
The Sun's position relative to the Earth changes throughout the year due to the tilt of the Earth's axis and its orbit around the Sun. At the equator, there are specific days when the Sun is directly overhead.
Key Dates of Sun's Direct Overhead Position
- The Sun is directly overhead at the equator on two specific dates:
- March 21 (Vernal Equinox)
- September 23 (Autumnal Equinox)
Reasons Behind These Dates
- Equinoxes Defined:
- An equinox occurs when the Earth's equator passes directly under the Sun, resulting in nearly equal day and night lengths.
- Sun's Direct Position:
- On these dates, the Sun's rays hit the equator at a 90-degree angle, meaning it is directly overhead at noon.
Why Other Options are Incorrect
- 21 June & 21 December:
- These dates correspond to the summer and winter solstices, where the Sun is at its highest and lowest points in the sky, respectively, but not directly overhead at the equator.
- 22 June & 22 December:
- Similar to the above, these dates also represent solstices.
- 20 March & 22 September:
- While close, the correct equinox dates are March 21 and September 23.
Conclusion
Thus, the correct answer is option 'B': March 21 and September 23, as these are the days when the Sun is directly overhead at the equator. Understanding these equinoxes is crucial for studying Earth's climate and seasonal changes.

Analysis of the Pairs
To determine how many pairs are correctly matched, let's evaluate each one based on astronomical facts.
1. Jupiter - Largest planet with 12 satellites
- Fact Check: Jupiter is indeed the largest planet in our solar system. However, as of current knowledge, it has 79 known moons (satellites), not just 12.
- Conclusion: Incorrectly matched.
2. Uranus - Orbits the sun in a clockwise direction from east to west
- Fact Check: Uranus is unique among the planets as it rotates on its side, causing it to have a retrograde rotation, which means it does spin clockwise when viewed from above the North Pole.
- Conclusion: Correctly matched.
3. Venus - Twice the distance from the sun compared to Earth
- Fact Check: Venus is actually closer to the Sun than Earth. The average distance from the Sun to Venus is about 0.72 AU (astronomical units), while Earth is 1 AU away.
- Conclusion: Incorrectly matched.
4. Neptune - Outermost planet visible with telescopes
- Fact Check: Neptune is indeed the outermost planet in our solar system, but it is not typically visible with the naked eye and requires telescopes for observation. The outermost planet visible is actually Uranus.
- Conclusion: Incorrectly matched.
Final Assessment
- Correctly Matched Pairs: Only one pair is correctly matched (Uranus).
- Total Correct Matches: Thus, the correct answer is option 'B' - Only two pairs.
This conclusion reflects an understanding of the accurate details regarding the planets in our solar system.

Understanding the Winter Solstice
The Winter Solstice is an important astronomical event, and it is crucial to analyze the given statements about it.
Statement 1: Correct
- The Winter Solstice occurs around December 21st in the Northern Hemisphere.
- At this time, the Earth's axis is tilted at approximately 23.5 degrees towards the Southern Hemisphere.
- Consequently, the Sun's rays strike the Tropic of Capricorn (23.5°S) directly, leading to the longest day in the Southern Hemisphere and the shortest day in the Northern Hemisphere.
Statement 2: Incorrect
- During the Winter Solstice, the Northern Hemisphere experiences its shortest day of the year, not the longest.
- This is because the tilt of the Earth causes the Sun to take a shorter path across the sky, resulting in fewer daylight hours.
Statement 3: Correct
- At the Equator, the duration of daylight is approximately 12 hours throughout the year.
- This consistency occurs because the Equator receives sunlight at a nearly perpendicular angle year-round, resulting in minimal variation in day length.
Conclusion
- Based on the analysis, only Statement 1 is accurate.
- Therefore, the correct answer is option 'A': 1 Only.
This clarity on the statements helps to understand the astronomical phenomena related to the Winter Solstice and its implications across different regions on Earth.

Understanding the Statements
To evaluate the correctness of the statements about Earth's rotation and its effects, let’s analyze each one carefully.
Statement 1: Earth's Axis Inclination
- The Earth's axis is indeed inclined at approximately 23.5° from the perpendicular to the plane of the ecliptic.
- This tilt is responsible for the changing seasons as the Earth orbits around the Sun.
- This statement is correct.
Statement 2: Velocity of Earth's Rotation
- The velocity of Earth's rotation is not greatest at the poles; it is actually greatest at the equator.
- This is due to the larger circumference at the equator compared to the poles, where the rotational speed decreases to zero.
- This statement is incorrect.
Statement 3: Weight Variations
- The weight of a body is actually less at the equator compared to the poles.
- This is due to the centrifugal force experienced at the equator, which counteracts gravitational pull, making objects weigh slightly less.
- This statement is incorrect.
Conclusion
- Based on the analysis, only Statement 1 is correct.
- Therefore, the correct answer is option 'A' (1 Only).
This breakdown clarifies the misconceptions in the other statements while affirming the correctness of the first statement about Earth's axial tilt.

Understanding the Statements
When analyzing the three statements regarding the Milky Way galaxy, Venus, and Neptune, it is essential to assess their accuracy:
1. The Milky Way galaxy contains approximately 100,000 million stars.
- This statement is correct. The Milky Way is estimated to have about 100 to 400 billion stars, commonly approximated as 100,000 million stars.
2. The planet Venus is located twice the distance from the Sun compared to Earth.
- This statement is incorrect. Venus is actually the second planet from the Sun, while Earth is the third. The average distance of Venus from the Sun is about 0.72 astronomical units (AU), whereas Earth's distance is about 1 AU. Thus, Venus is not twice as far from the Sun as Earth.
3. Neptune is the outermost planet in the solar system and is much colder than Uranus.
- This statement is also incorrect. While Neptune is often considered the outermost planet in our solar system, it is not significantly colder than Uranus. In fact, Neptune has a higher average temperature due to its internal heat. Uranus is generally colder in terms of atmospheric temperature.
Conclusion
Based on the evaluations:
- Only Statement 1 is correct.
- Therefore, the correct answer is option 'A' (1 Only).