In the following question a statement of assertion (A) is followed by a statement of reason (R )
A : Two large conducting spheres carrying charges `Q_(1) and Q_(2)` are brought close to each other. The magnitude of electrostatic force between them is exactly given by `Q_(1) Q_(2)// 4 pi epsilon_(0) r^(2)` , where r is the distance between their centres.
R: Here charges `Q_(1) and Q_(2)` can be assumed to be concentrated at the centres of their respective spheres.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion , then mark (1).
B. If both Assertion & Reason are true but the reason is not correct explanation of the assertion then mark (2)
C. If Assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements , then mark (4).

Answer

To solve the problem, we need to analyze the statements of assertion (A) and reason (R) provided in the question.

### Step 1: Understand the Assertion (A)
The assertion states that the magnitude of the electrostatic force between two large conducting spheres carrying charges \( Q_1 \) and \( Q_2 \) is given by the formula:

\[ F = \frac{Q_1 Q_2}{4 \pi \epsilon_0 r^2} \]

where \( r \) is the distance between their centers.

### Step 2: Analyze the Validity of Assertion (A)
This formula is derived from Coulomb's law, which applies to point charges. However, for large conducting spheres, the charge resides on the surface of the spheres, and the assumption that the charges can be treated as point charges is valid only when the distance \( r \) is much larger than the radius of the spheres. Therefore, while the assertion can be true under certain conditions, it is not universally applicable to all configurations of large conducting spheres.

### Step 3: Understand the Reason (R)
The reason states that the charges \( Q_1 \) and \( Q_2 \) can be assumed to be concentrated at the centers of their respective spheres.

### Step 4: Analyze the Validity of Reason (R)
In the case of conducting spheres, the charges actually reside on the surface of the spheres, not at their centers. Therefore, the reason provided is incorrect.

### Step 5: Conclusion
Both the assertion and the reason are false. The assertion is not universally valid for all configurations of large conducting spheres, and the reason is incorrect because the charges are on the surface, not at the centers.

### Final Answer
Both the assertion (A) and the reason (R) are false.

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