Before You Begin
Question #42007
The Question
A point charge is fixed at the origin of a coordinate system. A small planar sensor of area is constrained to move along the curve (where ) in the -plane. The sensor's surface normal is mechanically maintained parallel to the positive -axis (). The magnitude of the electric field at the sensor's location is determined experimentally by measuring the electric flux through the sensor, its area , and its -coordinate. During an experiment at , the relative error in measuring the flux is , and the relative error in measuring the area is . The absolute error in measuring the -coordinate is . Assuming the errors are independent and add up to give the maximum possible error, what is the maximum percentage relative error in the calculated value of the electric field ?
Options
- A.
- B.
- C.
- D.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Multi-Concept_Bridge
Master problems that require linking physics and math concepts to solve complex competitive questions.
Concepts Behind This Question
Flux and Surface Geometry|Relative Error Propagation in Powers
Why This Question Is Tricky
Common Mistakes
This question tests the rigorous application of Gauss's Law and error propagation by breaking the standard assumption of a spherical Gaussian surface.
Students often memorize the relative error formula and ignore the geometric coupling between the field vector and the surface normal.
By constraining the sensor to a non-spherical curve () with a fixed normal orientation, the effective area becomes a complex function of the coordinates.
The lethal trap is failing to account for the angular dependency () in the flux equation, which introduces a non-linear error propagation term from the -coordinate measurement.
Students who ignore the angle calculate , while those who incorrectly assume without resolving the dot product calculate .
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Units and Measurements - Class 11 Part 1 |
| Concept | Relative Error Propagation in Powers |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |