The energy stored in a capacitor is given by the formula: U=‌
q2
2C
where U is energy, q is charge, and C is capacitance. Step 2: Rearranging to Find Capacitance We can solve for C as follows: C=‌
q2
2U
Here, q=12×10−6C and U=6J. Substitute these values into the formula: C=‌
(12×10−6)2
2×6
Step 3: Calculate Capacitance Simplify the above equation: C=12×10−12F Step 4: Capacitance of a Spherical Conductor The capacitance of a spherical conductor is given by: C=4πε0r Step 5: Find the Radius Rearrange to find the radius r:r=‌
C
4πε0
We can also use ‌
1
4πε0
=9×109Nm2∕C2 so: r=9×109×12×10−12 Step 6: Solve for the Radius Multiply the values: r=108×10−3=0.108m=10.8cm