Assertion (A): The electric field due to point charge configuration with total charge zero is not zero.
Reason (R): Gauss law does not hold for a configuration with total charge zero.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
View Answer
Assertion (A) is true: an electric dipole (total charge zero) produces a non-zero electric field \(\propto 1/r^3\). Reason (R) is false: Gauss's Law \( \oint \vec{E} \cdot d\vec{A} = Q_{enc}/\epsilon_0\) is a fundamental law that always holds, regardless of the total charge.
Assertion (A): In a given situation of arrangement of charges, an additional charge is placed outside the Gaussian surface. In this situation, in the Gauss theorem \(\oint \vec{E}.d\vec{s} = \frac{q_{in}}{\epsilon_0}\) remains unchanged whereas electric field \(vec{E}\) is changed.
Reason (R): Electric field \(\vec{E}\) at any point on the Gaussian surface is due to inside charge only.
1. Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
View Answer
Assertion (A) is true. An external charge does not change the net charge enclosed by the Gaussian surface \(q_{in}\), so the total electric flux \(\oint \vec{E}.d\vec{s}\) remains unchanged as per Gauss's Law. However, the electric field \(\vec{E}\) at any point on the surface is the vector sum of fields from all charges, both inside and outside, so it will change. Reason (R) is false because the electric field at any point is due to both internal and external charges.
Assertion (A): Continuity equation explains conservation of electric charge.
Reason (R): Gauss law shows diversion when inverse square law is not obeyed.
1. (1) Both (A) & (R) are true and the (R) is the correct explanation of the (A)
2. (2) Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
3. (3) (A) is true but (R) is false
4. (4) Both (A) and (R) are false
View Answer
Continuity equation describes conservation of charge. Gauss's law is a fundamental law valid irrespective of the inverse square law and does not show 'diversion' based on its obedience. Thus, (A) is true, (R) is false.