General Science - MCQ Practice Questions

A solar eclipse happens when the Moon's orbit places it directly between Earth and the Sun, creating a shadow on Earth's surface.

This is distinct from a lunar eclipse where Earth blocks sunlight from reaching the Moon, and from penumbral or annular eclipses which are specific types with different characteristics.

The Oort Cloud remains theoretical and has never been directly observed; we infer its existence from comet trajectories and orbital studies.

While estimates suggest it contains billions to trillions of icy bodies, these objects are too distant and too small to be directly observed with current technology, making option D the incorrect statement among the given choices.

Venus's dense atmosphere (90 times denser than Earth's) is composed of 96.5% carbon dioxide with clouds of concentrated sulfuric acid, creating an extreme greenhouse effect with surface temperatures around 465°C.

This massive atmospheric composition traps far more infrared radiation than Earth's atmosphere, making it the primary cause of Venus's extreme greenhouse conditions rather than its orbital position alone.

The James Webb Space Telescope operates primarily in infrared wavelengths (0.6-28 micrometers), which penetrates dust clouds that block visible light, allowing it to observe star-forming regions, protoplanetary disks, and extremely distant galaxies from the early universe.

Infrared observations also reveal objects too cool or distant to be seen in visible light, making it superior for studying the universe's earliest structures and most distant objects.

Mercury is closest to Sun.