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Question #42933
The Question
A solid non-conducting sphere of radius (in meters) has a uniform volume charge density (in ). The sphere is centered at the origin of a Cartesian coordinate system. A spherical cavity of radius is created inside the sphere, with its center located at . The entire setup is placed in an external electric field given by , where and are the coordinates in meters. Find the coordinates of the neutral point (the point where the net electric field is zero) inside the cavity. Assume the permittivity of free space is .
Options
- A.
- B.
- C.
- D.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Intuition_Breaker
Train your brain to resist "obvious" answers that are designed to deceive your intuition.
Concepts Behind This Question
Non-conducting Charged Sphere|Neutral Equilibrium Points|Cavity Field Shielding
Why This Question Is Tricky
Common Mistakes
This question tests the student's ability to distinguish between the electrostatic properties of conducting and non-conducting materials with cavities.
A common lethal mistake (the 'shielding trap') is assuming that the electric field inside any cavity is zero, misapplying the Faraday cage effect of conductors to a non-conducting charge distribution.
If a student falls for this trap, they will incorrectly assume and solve only for , leading to the origin .
Furthermore, it rigorously tests the superposition principle and vector addition of fields, ensuring students can handle 3D coordinate geometry alongside Gauss's Law.
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Electric Charges and Fields - Class 12 |
| Concept | Non-conducting Charged Sphere |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |