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Q1.17: NCERT Physics - Part 1 UNITS AND MEASUREMENT 1.17 Solution: The Sun is a hot plasma (ionized matter) with its inner core at …

⚠️ Common Exam Traps & Conceptual Pitfalls

Students often assume that because the Sun is a hot plasma (gas-like phase), its density must be in the range of gases ($10^{-3}$ to $10^2$ kg/m$^3$). However, the Sun's immense mass compressed by gravity results in a density of $sim 10^3$ kg/m$^3$, which is comparable to solids and liquids, not gases.

The Sun is a hot plasma (ionized matter) with its inner core at a temperature exceeding 10_ 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 = 2.0×10302.0 \times 10^{30} kg, radius of the Sun = 7.0×1087.0 \times 10^8 m.

Step-by-Step Verified Solution

**Answer:** Density = 1.4×103 kg m−31.4 \times 10^3 \text{ kg m}^{-3}, which is in the range of solids/liquids. **Step-by-Step Explanation:** Volume of Sun = 43πR3=43π(7.0×108)3=1.44×1027 m3\frac{4}{3}\pi R^3 = \frac{4}{3}\pi (7.0 \times 10^8)^3 = 1.44 \times 10^{27} \text{ m}^3. Density = MV=2.0×10301.44×1027=1.39×103 kg m−3\frac{M}{V} = \frac{2.0 \times 10^{30}}{1.44 \times 10^{27}} = 1.39 \times 10^3 \text{ kg m}^{-3}. This is in the range of solids and liquids (density of water = 103 kg m−310^3 \text{ kg m}^{-3}).

All Questions in this Chapter

Q1.1 Q1.2 Q1.3 Q1.4 Q1.5 Q1.6 Q1.7 Q1.8 Q1.9 Q1.10 Q1.11 Q1.12 Q1.13 Q1.14 Q1.15 Q1.16 Q1.17

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