Question

Given below are two statement: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : If an electric dipole of dipole moment 30 x 10-5 Cm is enclosed by a closed surface, the net flux coming out of the surface will by zero.
Reason R : Electric dipole consists of two equal and opposite charges.
In the light of above, statements, choose the correct answer from the options given below:

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R true but R is NOT the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Answer 1

The Correct Option is A

The given question involves two statements: an assertion (A) and a reason (R). We need to evaluate the truth of these statements and determine the relationship between them. Let's break down each statement:

1. Assertion (A): If an electric dipole of dipole moment 30 \times 10^{-5} \, \text{Cm} is enclosed by a closed surface, the net flux coming out of the surface will be zero.
2. Reason (R): An electric dipole consists of two equal and opposite charges.

To decide whether each statement is true and if the reason explains the assertion, let's consider the concepts involved:

• An electric dipole is a system of two equal and opposite charges separated by a small distance. The net charge of a dipole is zero because the positive and negative charges cancel each other out.
• Gauss's Law: According to Gauss's Law, the electric flux \Phi\ through a closed surface is given by the expression: \Phi = \frac{Q_{\text{enc}}}{\varepsilon_0}, where Q_{\text{enc}} is the net charge enclosed by the surface and \varepsilon_0 is the permittivity of free space.
• For an electric dipole enclosed by a closed surface, Q_{\text{enc}} = 0 because there are equal amounts of positive and negative charges, making the total charge zero.

Given this understanding, Assertion (A) is true because the net charge enclosed by the surface is zero, leading to zero net electric flux.

Reason (R) is also true. An electric dipole inherently consists of two equal and opposite charges.

Now, we must determine if R explains A. The reason correctly explains why the net flux is zero: it is because the dipole has no net charge within the closed surface.

Therefore, the correct answer is: Both A and R are true and R is the correct explanation of A.