Which of the following `"is"//"are"` the examples of induced radioactivity?

Options

A. `._(7)N^(14) + ._(2)He^(4) rarr ._(8)O^(17) + ._(1)H^(1)`
B. `._(4)Be^(9) + ._(1)H^(1) rarr ._(3)Li^(9) + ._(2)He^(4)`
C. `._(12)Mg^(24) + ._(2)He^(4) rarr ._(14)Si^(27) + ._(0)n^(1)`
D. `._(5)B^(10) + ._(2)He^(4) rarr ._(7)N^(13) + ._(0)n^(1)`

Explanation

To determine which of the following are examples of induced radioactivity, we need to understand the concept of induced radioactivity, also known as artificial radioactivity. This process involves the conversion of one element into another through artificial means, typically by bombarding the target element with fundamental particles.

### Step-by-Step Solution:

1. **Understanding Induced Radioactivity**:
- Induced radioactivity occurs when a stable nucleus is bombarded with particles (like protons, neutrons, or alpha particles), resulting in the formation of a new radioactive nucleus.

2. **Analyzing Each Option**:
- **Option 1**: Nitrogen-14 (₇N) is bombarded with an alpha particle (helium nucleus) to produce Oxygen-17 (₈O). Since this process involves bombarding nitrogen with a fundamental particle and results in a radioactive product, this is an example of induced radioactivity.

- **Option 2**: Beryllium (₄Be) reacts with a proton (protium) to produce Lithium-9 (₃Li). The reaction involves a fundamental particle (proton) and results in a radioactive element, making this an example of induced radioactivity.

- **Option 3**: Magnesium (₁₂Mg) is bombarded with an alpha particle, resulting in Silicon-27 (₁₄Si). This reaction also involves a fundamental particle and produces a radioactive element, classifying it as induced radioactivity.

- **Option 4**: Boron (₅B) is bombarded with an alpha particle, producing Nitrogen-13 (₇N). This reaction involves a fundamental particle and results in a radioactive product, confirming it as an example of induced radioactivity.

3. **Conclusion**:
- All four options provided are examples of induced radioactivity.

### Final Answer:
All of the options listed are examples of induced radioactivity.