Final answer:
The false statement about the tails of comets is that 'Tails of comets are always visible even when the comet is far from the Sun.' Tails are only formed and visible when comets are close enough to the Sun for sublimation of volatile materials to occur.The correct option is C
Step-by-step explanation:
To address the question about the tails of comets, let's first clarify that comets indeed have two kinds of tails: the ion tail and the dust tail. The ion tail consists of ionized gases which always points directly away from the Sun, due to the influence of the solar wind, which is composed of charged particles like protons and electrons. On the other hand, the dust tail is made up of tiny solid particles that, while also generally pointing away from the Sun, shows a slight curve as it follows the comet's orbit due to the momentum transfer from photons.
Now, referring to the statements provided:
A) The ion tail always points away from the Sun - This is true, as the solar wind strongly influences the ionized particles.
B) The dust tail is composed of tiny solid particles - This is also true, as explained with the photon momentum transfer.
D) Tails are formed due to the sublimation of volatile materials in the comet - This statement is true. The sublimation of materials due to solar heat creates the gases and dust that form the tail.
Therefore, the false statement is:
C) Tails of comets are always visible even when the comet is far from the Sun - This statement is false. When comets are far from the Sun, the sublimation rate drops significantly or stops, and as a result, the tails may not be visible or not present at all.
The correct option is C: Tails of comets are always visible even when the comet is far from the Sun.