Electrostatics 4 Question 14
14. An elliptical cavity is carved within a perfect conductor. A positive charge is placed at the centre of the cavity. The points and are on the cavity surface as shown in the figure. Then
(1999, 3M)
(a) electric field near
(b) charge density at
(c) potential at
(d) total electric field flux through the surface of the cavity is
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Answer:
Correct Answer: 14. (c, d)
Solution:
- Under electrostatic condition, all points lying on the conductor are at same potential. Therefore, potential at
potential at . Hence, option (c) is correct. From Gauss theorem, total flux through the surface of the cavity will be .
NOTE
Instead of an elliptical cavity, if it would had been a spherical cavity then options (a) and (b) were also correct.