Every free question on Space & Astronomy (General Science) from past WBCS Preliminary Examination and WBCS Main Examination papers, newest first, each with its answer and a short explanation. Free to read.
Answer: (B) SYNCOM-3
Syncom 3, launched by NASA in August 1964, was the first geostationary satellite and relayed TV coverage of the 1964 Tokyo Olympics. Anik (1972) and Westar (1974) came later, and Molniya satellites used highly elliptical, not geostationary, orbits.
Answer: (C) 5000
The Sun's visible surface (photosphere) is at about 5,800 K while Earth's surface averages about 288 K, so the Sun is hotter by more than 5000 kelvin. 1000 K and 500 K understate the gap, and 1,00,000 K is far above the surface temperature.
Answer: (C) 1 : 4
The Moon's diameter is about 3,474 km and the Earth's about 12,742 km, a ratio of roughly 0.27, i.e., nearly 1 : 4. Related ratios worth remembering: the Moon's mass is about $\frac{1}{81}$ of the Earth's, its surface gravity about $\frac{1}{6}$ and its volume about $\frac{1}{49}$. It rotates on its axis and revolves around the Earth in the same period of about 27.3 days, so we always see the same face; its mean distance is about 3,84,400 km, and moonlight takes about 1.3 seconds to reach us.
