A: Both the Thomson's as well as the Rutherford's models constitute an unstable system.
R: Thomson's model is unstable electrostatically while Rutherford's model is unstable because of electromagnetic radiation of orbiting electrons.

Options

A. If both Assertion & Reason are true and the reason is the correct explantion of the assertion , then mark (1)
B. if both Assertion & Reason are true but the reason is not the correct explantion 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 assertion and reason-based question, we need to analyze both the assertion (A) and the reason (R) provided.

### Step 1: Understand the Assertion
The assertion states that both Thomson's and Rutherford's models constitute an unstable system.

- **Thomson's Model**: Known as the "plum pudding model," it suggests that electrons are embedded in a positively charged "soup." However, this model is unstable because the distribution of charge does not hold under electrostatic forces. The electrons would repel each other due to their negative charges, leading to instability.

### Step 2: Understand the Reason
The reason provided states that Thomson's model is unstable electrostatically, while Rutherford's model is unstable because of electromagnetic radiation from orbiting electrons.

- **Rutherford's Model**: This model describes electrons orbiting a dense nucleus. According to Maxwell's theory, any charged particle (like an electron) moving in a circular path emits electromagnetic radiation. As electrons lose energy through this radiation, they spiral into the nucleus, leading to instability.

### Step 3: Analyze the Relationship Between A and R
- The assertion (A) claims both models are unstable, which is true based on the explanations given.
- The reason (R) explains why each model is unstable, which is also correct.

### Step 4: Conclusion
Since both the assertion and the reason are true, and the reason correctly explains the assertion, we can conclude that the answer is that both A and R are correct, with R being the correct explanation for A.

### Final Answer
Both the assertion and reason are true, and the reason correctly explains the assertion.

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