Which of the following statement(s) is/are correct?
(A) If the electric field due to a point charge varies as instead of , then the Gauss law will still be valid.
(B) The Gauss law can be used to calculate the field distribution around an electric dipole.
(C) If the electric field between two point charges is zero somewhere, then the sign of the two charges is the same.
(D) The work done by the external force in moving a unit positive charge from point at potential to point at potential is .
(A) If the electric field due to a point charge varies as instead of , then the Gauss law will still be valid.
(B) The Gauss law can be used to calculate the field distribution around an electric dipole.
(C) If the electric field between two point charges is zero somewhere, then the sign of the two charges is the same.
(D) The work done by the external force in moving a unit positive charge from point at potential to point at potential is .
- (A)Statement A
- (B)Statement B
- (C)Statement C✓ Correct
- (D)Statement D✓ Correct
Answer: (C), (D)
Solution
(A) False: Gauss's law is derived from the inverse-square law; it would not hold for . (B) False: Gauss's law cannot easily calculate field distribution for a dipole due to lack of symmetry. (C) True: For the field to be zero between two charges, they must have the same sign (both positive or both negative). (D) True: Work done by external force against electrostatic force is ; for unit charge, .
JEE Advanced · 2011 · 10 Apr 2011 · Paper 2 · One or more correct options