which of the following systems may be adequately described by classical physics?

Options

A. motion of a cricket ball
B. motion of a dust particle
C. a hydrogen atom
D. a neutron changing to a proton

Answer

To determine which of the given systems may be adequately described by classical physics, we need to understand the distinction between classical physics and quantum physics.

### Step-by-Step Solution:

1. **Understand Classical Physics**:
Classical physics describes the behavior of macroscopic objects, typically those larger than \(10^{-6}\) meters (1 micron). It includes laws such as Newton's laws of motion, Newton's law of gravitation, Maxwell's equations of electromagnetism, and thermodynamics.

**Hint**: Remember that classical physics works well for larger objects and systems.

2. **Identify the Options**:
The options given are:
- Motion of a cricket ball
- Motion of dust particles
- A hydrogen atom
- A neutron changing to a proton

3. **Analyze Each Option**:
- **Motion of a cricket ball**: This is a macroscopic object, much larger than \(10^{-6}\) meters. Therefore, it can be adequately described by classical physics.
- **Motion of dust particles**: Dust particles are also macroscopic and larger than \(10^{-6}\) meters, so they can also be described by classical physics.
- **A hydrogen atom**: A hydrogen atom is a subatomic particle, with a size much smaller than \(10^{-6}\) meters. This falls under quantum physics.
- **A neutron changing to a proton**: This process involves subatomic particles and is also governed by quantum physics.

4. **Conclusion**:
Based on the analysis, the systems that can be adequately described by classical physics are:
- Motion of a cricket ball
- Motion of dust particles

Therefore, the correct options are the first and second options.

### Final Answer:
The systems that may be adequately described by classical physics are:
- Motion of a cricket ball
- Motion of dust particles