Answer:
1.31×10^-9 C
Explanation:
Total charge = volume density × volume of sphere
Volume density = 6.1×10^-4 C/m^3
Volume of sphere = 4π/3×(outer radius - inner radius)^3 = 4×3.142/3 × (4.5 - 3.7)^3 = 4.189×0.8^3 = 2.145 cm^3 = 2.145×10^-6 m^3
Total charge = 6.1×10^-4 × 2.145×10^-6 = 1.31×10^-9 C