General Science — MCQ Practice Questions & Answers

Question 1

What is the primary reason why Venus experiences a runaway greenhouse effect compared to Earth, despite being only slightly closer to the Sun?

Accepted Answer

Correct answer: A. Venus has a much thicker atmosphere composed primarily of carbon dioxide with clouds of sulfuric acid — 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.

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B. Venus rotates much faster than Earth, trapping more heat

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C. Venus lacks a magnetic field to protect it from solar radiation

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D. Venus is larger in size and therefore has greater gravitational compression

Question 2

The James Webb Space Telescope observes primarily in which wavelength region of the electromagnetic spectrum, and what is the key advantage of this choice?

Accepted Answer

Correct answer: C. Infrared; allows observation through cosmic dust and enables viewing of early universe objects — 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.

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A. Ultraviolet; better for observing hot, young stars

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B. Visible light; provides clearest images of the universe

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D. Microwave; measures the cosmic microwave background radiation directly

General Science - MCQ Practice Questions