Q 2.23: The Sun is a hot plasma (ionized matter) with its inner core at a temperature exceeding 10^7 K, and its outer surface at a temperature of about 6000 K. At these high temperatures, no substance remains in a solid or liquid phase. In what range do you expect the mass density of the Sun to be, in the range of densities of solids and liquids or gases? Check if your guess is correct from the following data: mass of the Sun = 2.0 \times 10^{30} kg, radius of the Sun = 7.0 \times 10^8 m

Answers (1)
S safeer


Mass of the Sun, m = 3 \times10^{30}\ kg

The radius of the Sun, r = 8 \times10^8\ m

\therefore Volume V = \frac{4}{3}\pi r^3

\frac{4}{3} \times \frac{22}{7} \times (8 \times 10^8)^3 = 2145.52 \times10^{24} m^3

  Density = Mass/Volume 

\frac{3\times10^{30}}{2145.52\times10^{24}} = 1.39 \times 10^3\ kgm^{-3}

Therefore, the density of the sun is in the range of solids and liquids and not gases. This high density arises due to inward gravitational attraction on outer layers due to inner layers of the Sun. (Imagine layers and layers of gases stacking up like a pile!)