Assertion (A ): In the `alpha`-particle scattering experiment most of the `alpha`-particles pass undeviated.
Reason (R ): Most of the space in the atom is empty.

Options

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

Explanation

To analyze the assertion and reason provided in the question, let's break it down step by step:

### Step 1: Understanding the Assertion
The assertion states that "In the alpha-particle scattering experiment, most of the alpha particles pass undeviated." This refers to the results of the Rutherford gold foil experiment, where a beam of alpha particles was directed at a thin foil of gold.

### Step 2: Evaluating the Assertion
In the experiment, it was observed that a significant majority of the alpha particles (about 99.86%) passed straight through the foil without any deflection. This observation supports the assertion that most alpha particles pass undeviated.

### Step 3: Understanding the Reason
The reason given is "Most of the space in the atom is empty." This statement is based on the structure of the atom, where the nucleus occupies a very small volume compared to the overall size of the atom. Most of the atom is indeed empty space.

### Step 4: Evaluating the Reason
The reason is valid because the fact that most of the space in an atom is empty explains why most alpha particles pass through without deflection. Since there is very little matter in the atom (the nucleus is small compared to the overall size of the atom), the likelihood of an alpha particle colliding with the nucleus is low.

### Step 5: Conclusion
Both the assertion and the reason are true, and the reason provides a correct explanation for the assertion. Therefore, the correct conclusion is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.

### Final Answer
Both assertion (A) and reason (R) are true, and R is the correct explanation of A.

---