NEET Physics Question - Electrostatics

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.

Both (A) & (R) are true and the (R) is the correct explanation of the (A)

Both (A) & (R) are true but the (R) is not the correct explanation of the (A)

(A) is true but (R) is false

Both (A) and (R) are false

Solution:

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.

Rankers Physics

Gauss’s Law and External Charges

Solution:

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