Final answer:
To calculate the total charge enclosed by the solid, we need to consider the charge density and volume of the solid. Without the outer radius of the spherical solid, we cannot determine the charge, so the answer is that the total charge cannot be determined.
Step-by-step explanation:
To compute the total charge enclosed by the insulating spherical charged solid, we must consider both the point charge inside the cavity and the charge contributed by the solid itself. The charge density (ρ) inside the solid is given as 7.35 × 10⁻⁴ C/m³. The volume (V) of the solid that contributes to the charge can be found by subtracting the volume of the cavity from the volume of the entire sphere.
The volume of the entire sphere is given by V = 4/3 π r³, where r is the radius of the sphere. The volume of the cavity is also given by V = 4/3 π r³, but with the radius of the cavity instead of the radius of the entire sphere. We therefore have:
Vsolid = 4/3 π R³ - 4/3 π r³
where R is the outer radius of the spherical solid (not given in the problem), and r = 6.80 × 10⁻² m is the radius of the inner cavity.
The charge within the solid portion is ρ Vsolid and the total charge enclosed by the solid, Qtotal, is the sum of the charge of the point charge and the charge within the solid portion:
Qtotal = Qcavity + ρ Vsolid
Since we know Qcavity = -3.00 × 10⁻⁶ C (the point charge) and we can calculate the charge in the solid using the given density ρ and Vsolid, we can find Qtotal.
Without the outer radius R of the spherical solid, we cannot compute the exact value of Qtotal. Thus, the total charge enclosed by the solid cannot be determined with the information provided. Therefore, the correct answer to the student's question is 1) Cannot be determined.