Geodesy and Celestial Mechanics

Carbon is the 17th most abundant element in Earth's crust, comprising approximately 0.02% by mass. This makes it relatively rare compared to major elements like oxygen, silicon, aluminum, and iron, but more abundant than many trace elements.

This is the correct matching.

Earth's shape is oblate spheroid.

This is the correct answer. This is the standard meridian of India.

The correct answer is 40075 km because this is the approximate equatorial circumference of Earth. The meridional circumference is slightly less at about 40,008 km. The value 40,075 km represents the standard measurement used in geography and is the distance around Earth at the equator.

A solar day - the time from noon to noon - is exactly 24 hours. While Earth's sidereal rotation (one complete turn relative to stars) is about 23 hours 56 minutes, the 24-hour cycle is what we experience as daylight and darkness. Options A, C, and D are not rotation periods.

A globe is a three-dimensional scale model of Earth and is the most accurate representation of our planet's shape. Maps are flat and distort distances, areas, or shapes. Topography sheets show terrain but not the whole Earth. Only a globe captures the spherical nature.

Longitude lines run from the North Pole to the South Pole (meridians). Latitude lines run east-west parallel to the equator. 'Parallels' specifically refers to latitude lines, not longitude. Option D is incorrect because these are distinct systems.

The upper limit of Earth's atmosphere extends to approximately 10,000 km, which is about half the distance to the Moon. While the Kármán line (100 km) marks the boundary of space, atmospheric particles exist much farther out, gradually thinning until they merge with the solar wind.

Earth is not a perfect sphere but an oblate spheroid - slightly flattened at the poles and bulging at the equator due to Earth's rotation. The equatorial diameter is about 43 km larger than the polar diameter. This shape was confirmed by measurements and is consistent with physics of rotating bodies.

At the equator, day and night are approximately equal (12 hours each) throughout the year. This is because the equator always receives about 12 hours of daylight due to Earth's axial orientation relative to the sun. The duration varies more at higher latitudes with seasons.

The distance between two consecutive latitudes is approximately 111 km (69 miles). This is because lines of latitude are parallel circles and the distance between them is calculated based on Earth's circumference of about 40,075 km divided by 360 degrees.

The Prime Meridian is the 0° longitude line, which passes through Greenwich, London. It serves as the reference point from which all other longitudes are measured. Longitudes west of this line are labeled W and east are labeled E.

The Tropic of Capricorn is located at 23½° S (south) latitude. It marks the southernmost point where the sun appears directly overhead at noon during the December solstice. The 66½° latitudes refer to the Arctic and Antarctic Circles.

The Equator is the imaginary line of 0° latitude that divides the Earth into Northern and Southern Hemispheres. It is the reference point from which all other latitudes are measured north or south.