universe & solar system section 4 Practice Questions Answers Test with Solutions & More Shortcuts

Answer: (d)

The Milky Way is the galaxy that contains our solar system. This name derives from its appearance as a dim “milky” glowing band arching across the night sky, in which the naked eye cannot distinguish individual stars.

Observational evidence for the Milky Way is made up of distant stars first came when Galileo pointed his telescope towards the Milky Way, observing a large number of faint stars.

Answer: (a)

Venus is called the Evening star. Because it trails the Sun in the sky and brightens into view immediately after the Sun sets and when the sky is dark enough. When Venus is at its brightest, it appears visible merely minutes after the Sun has set.

Answer: (b)

The planet Pluto has been declared a dwarf planet at the summit held in Prague. In August 2006 the International Astronomical Union (IAU) downgraded the status of Pluto to that of a “dwarf planet.”

This means that from now on only the rocky worlds of the inner Solar System and the gas giants of the outer system will be designated as planets.

Answer: (b)

The sun radiates vast quantities of energy into space, across a wide spectrum of wavelengths. Most of the radiant energy from the sun is concentrated in the visible and near-visible parts of the spectrum.

The narrow band of visible light, between 400 and 700 nm, represents 43% of the total radiant energy emitted. Wavelengths shorter than the visible account for 7 to 8% of the total, but are extremely important because of their high energy per photon. The shorter the wavelength of light, the more energy it contains.

Answer: (c)