Back to Directory
NEET PHYSICSEasy

If RR is the radius of the earth and gg is the acceleration due to gravity on the earth surface. Then the mean density of the earth will be:

A

πRG12g\frac{\pi R G}{12 g}

B

3πR4gG\frac{3 \pi R}{4 g G}

C

3g4πRG\frac{3 g}{4 \pi R G}

D

4πG3gR\frac{4 \pi G}{3 g R}

Step-by-Step Solution

  1. Formula for g: The acceleration due to gravity (gg) on the surface of the Earth is related to its mass (MM) and radius (RR) by the formula: g=GMR2g = \frac{GM}{R^2}
  2. Mass in terms of Density: Assuming the Earth is a sphere of uniform mean density (ρ\rho), its mass is given by volume times density: M=43πR3ρM = \frac{4}{3}\pi R^3 \rho
  3. Substitution and Solving: Substitute the expression for MM into the equation for gg: g=GR2(43πR3ρ)g = \frac{G}{R^2} \left( \frac{4}{3}\pi R^3 \rho \right) g=43πGRρg = \frac{4}{3} \pi G R \rho Rearranging to solve for density (ρ\rho): ρ=3g4πGR\rho = \frac{3g}{4 \pi G R}
Practice Mode Available

Master this Topic on Sushrut

Join thousands of students and practice with AI-generated mock tests.

Get Started