Who discovered neutron?

Options

A. James Chadwick
B. Ernest Rutherford
C. Marie and Pierre Curie
D. Albert Einstein.

Explanation

To solve the question "Who discovered neutron?", we can follow these steps:

### Step 1: Identify the options given in the question.
The options provided are:
1. James Chadwick
2. Ernest Rutherford
3. Marie Curie
4. Albert Einstein

### Step 2: Recall the contributions of each scientist.
- **James Chadwick**: Known for the discovery of the neutron in 1932.
- **Ernest Rutherford**: Known for his work on the structure of the atom and the discovery of the proton.
- **Marie Curie**: Known for her research on radioactivity and the discovery of radium and polonium.
- **Albert Einstein**: Known for the theory of relativity and contributions to quantum mechanics, but not for the discovery of the neutron.

### Step 3: Determine who discovered the neutron.
From our recall, James Chadwick is the scientist who discovered the neutron in 1932.

### Step 4: Verify the information.
James Chadwick was awarded the Nobel Prize in Physics in 1935 for his discovery of the neutron. This confirms that he is indeed the correct answer.

### Step 5: Select the correct option.
The correct answer to the question is **option number 1: James Chadwick**.

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