Which of the following `"is"//"are" correct?

Options

A. `alpha`-rays are more penetrating then `beta`-rays.
B. `alpha`-rays have greater ionizing power than `beta`-rays.
C. `beta`-particles are not present in the elements, yet they are emitted from the nucleus.
D. `alpha`-rays are not emitted simultaneously with `alpha`- and `beta`-rays.

Answer

**Step-by-Step Solution:**

1. **Understanding Alpha and Beta Rays:**
- Alpha rays consist of alpha particles, which are made up of 2 protons and 2 neutrons (essentially helium nuclei).
- Beta rays consist of beta particles, which are high-energy, high-speed electrons or positrons emitted by certain types of radioactive decay.

2. **Analyzing the First Statement:**
- The first statement claims that alpha rays are more penetrating than beta rays.
- This statement is incorrect. Beta particles (electrons) are more penetrating than alpha particles because they are lighter and can travel through materials more easily.

3. **Analyzing the Second Statement:**
- The second statement claims that alpha rays have greater ionizing power than beta rays.
- This statement is correct. Alpha particles have a greater ionizing power because they are heavier and carry a double positive charge, which allows them to ionize atoms more effectively as they pass through matter.

4. **Conclusion:**
- Based on the analysis, the first statement is incorrect, and the second statement is correct.

**Final Answer:**
- The first statement is incorrect, and the second statement is correct.

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