Which is incorrect statement in the following ?

Options

A. `alpha` - rays have more penetrating power than `beta` - rays
B. `alpha` - rays have less penetrating power than `gamma` - rays
C. `beta` - rays have less penetrating power than `gamma` - rays
D. `beta` - rays have more penetrating power than `alpha` - rays

Answer

To determine the incorrect statement among the given options regarding the penetrating power of alpha, beta, and gamma rays, we can analyze each option based on the known properties of these types of radiation.

### Step-by-Step Solution:

1. **Understanding the Types of Rays:**
- There are three types of radiation emitted during radioactive decay: alpha rays (α), beta rays (β), and gamma rays (γ).
- Each type of ray has different penetrating powers.

2. **Penetrating Power Order:**
- **Gamma rays (γ)** have the highest penetrating power.
- **Beta rays (β)** have intermediate penetrating power.
- **Alpha rays (α)** have the lowest penetrating power.

3. **Analyzing Each Option:**
- **Option 1:** "Alpha rays have more penetrating power than beta rays."
- This statement is incorrect because alpha rays have the least penetrating power compared to beta rays.
- **Option 2:** "Alpha rays have less penetrating power than gamma rays."
- This statement is correct since gamma rays have the highest penetrating power.
- **Option 3:** "Beta rays have less penetrating power than gamma rays."
- This statement is also correct as gamma rays penetrate more than beta rays.
- **Option 4:** "Beta rays have more penetrating power than alpha rays."
- This statement is correct because beta rays do indeed have more penetrating power than alpha rays.

4. **Conclusion:**
- The only incorrect statement among the options is **Option 1**, which claims that alpha rays have more penetrating power than beta rays.

### Final Answer:
The incorrect statement is **Option 1: Alpha rays have more penetrating power than beta rays.**