Astronomy

The Fraunhofer D-lines are dark absorption lines in the solar spectrum caused by sodium in the sun's outer atmosphere (photosphere/chromosphere). These cooler layers absorb specific wavelengths, creating dark lines in the otherwise continuous spectrum.

It last appeared in 1986. Halley's Comet is seen after every 76 years.

Correct Answer: Triton
Triton is the largest natural satellite of the planet Neptune. It was discovered on October 10, 1846 by English astronomer William Lassell.

Sirius B is a white dwarf, one of the three “classics”, discovered to be white dwarf stars in the early years of the 20^th century (Sirius B was the second to be discovered – 40 Eridani B had been found much earlier.)

Statement 1 is incorrect. Uttarayan (the sun's apparent northward movement) begins after the winter solstice (December 21-22), not after the summer solstice. The summer solstice (around June 21) marks the beginning of Dakshinayan (southward movement). Statement 2 is correct. The sun rises due east only on the two equinoxes (March 21 and September 23). On other days, it rises either north of east (during Uttarayan) or south of east (during Dakshinayan) due to Earth's axial tilt.

Uranus was the first planet discovered with the help of a telescope. William Herschel discovered it in 1781 using a telescope he built himself. Before this discovery, only the five planets visible to the naked eye (Mercury, Venus, Mars, Jupiter, and Saturn) were known. Pluto was discovered much later (1930) and is now classified as a dwarf planet. Saturn was known to ancient civilizations long before the telescope was invented.

Ceres is the largest object in the asteroid belt between Mars and Jupiter. It was discovered in 1801 and classified as a planet for many years before being reclassified as an asteroid in the 1850s. Since 2006, it has been designated as a dwarf planet. The asteroid belt, where Ceres resides, lies in the gap between the orbits of Mars and Jupiter, making option B the correct answer.

Proxima Centauri is the closest known star to the Sun and part of the Alpha Centauri star system. It is located approximately 4.24 light-years away from Earth, making it the nearest stellar neighbor to our solar system.

Ceres is indeed the largest object in the asteroid belt between Mars and Jupiter, with a diameter of about 950 km. However, statement 2 is incorrect because asteroids are found between Mars and Jupiter, not Mars and Saturn.