Before You Begin
Question #42764
The Question
A large tank contains a liquid of uniform density . The tank accelerates horizontally to the right ( direction) with a constant acceleration . A rigid, thin-walled, uncharged conducting spherical shell of outer radius is completely submerged in the liquid and held fixed relative to the tank. The cavity inside the shell contains a gas of negligible mass. A point charge is held fixed at the exact center of the cavity. A uniform external electric field is applied horizontally to the right. Let be the net electrostatic force exerted on the point charge . Let be the difference in mechanical pressure between the leftmost point () and the rightmost point () on the outer surface of the shell. Let be the difference in gas pressure between the leftmost point () and the rightmost point () on the inner surface of the shell. Which of the following sets of values is correct?
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
Cavity Field Shielding|Conservative Field Path Independence|Accelerated Frame Hydrostatics
Why This Question Is Tricky
Common Mistakes
This question tests the student's ability to decouple mechanical and electrostatic equilibrium in an accelerated frame.
A common trap is assuming that the external tilted effective potential (due to non-inertial acceleration) penetrates the cavity, leading students to incorrectly assign a pressure gradient to the internal massless gas ().
Furthermore, students often misapply the superposition principle, thinking the external electric field acts on the internal charge , failing to recognize that the conducting shell provides perfect electrostatic shielding (Faraday cage effect) while simultaneously providing mechanical shielding against the external pressure gradient.
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Electrostatic Potential and Capacitance - Class 12 |
| Concept | Cavity Field Shielding |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |