Question

The radius of the sun is $7\times {10}^{8}m$ and its mass is $2\times {10}^{30}kg$. What is the order of magnitude of density of the sun?

• A. $1.4\times {10}^{3}kg/m^3$
• B. ${10}^{7}kg/m^3$
• C. $1.5\times {10}^{3}kg/m^3$
• D. ${10}^{3}kg/m^3$

Answer 1

The correct option is D ${10}^{3}kg/m^3$

Given : $R=7\times {10}^{8}m$ and $M=2\times {10}^{30}kg$
Volume of sun $V=\frac{4}{3}\pi R^3=\frac{4}{3}\pi \times (7\times {10}^8{)}^3=1.4\times {10}^{27}{m}^3$
Density of sun $\rho =\frac{M}{V}=\frac{2\times {10}^{30}}{1.4\times {10}^{27}}=1.43\times {10}^{3}kg/m^3$
Thus order of magnitude of density of sun is ${10}^{3}kg/m^3$.