Cathode rays have same charge to mass ratio as

Options

A. `alpha`-particles
B. `beta`-rays
C. Anode rays
D. Protons

Explanation

To solve the question "Cathode rays have the same charge to mass ratio as," we will analyze the properties of cathode rays and compare them with the given options.

### Step-by-Step Solution:

1. **Understanding Cathode Rays**:
- Cathode rays are streams of electrons emitted from the cathode in a vacuum tube.
- They carry a negative charge and have a specific mass.

2. **Charge to Mass Ratio of Cathode Rays**:
- The charge to mass ratio (q/m) for cathode rays is defined as the charge of an electron divided by its mass.
- Mathematically, this can be expressed as:
\[ \frac{q}{m} = \frac{-e}{m_e} \]
where \( e \) is the charge of the electron and \( m_e \) is the mass of the electron.

3. **Comparing with Other Rays**:
- **Alpha Particles**:
- Alpha particles consist of 2 protons and 2 neutrons (He²⁺).
- They have a positive charge (due to protons) and a much larger mass compared to electrons.
- Therefore, the charge to mass ratio of alpha particles is different from that of cathode rays.

- **Beta Rays**:
- Beta rays are essentially electrons (or positrons, which are positively charged).
- Since beta rays consist of electrons, their charge to mass ratio is the same as that of cathode rays.
- Thus, we can say:
\[ \frac{q}{m} \text{ (beta rays)} = \frac{q}{m} \text{ (cathode rays)} \]

- **Anode Rays**:
- Anode rays consist of positively charged ions, typically formed by the removal of electrons from gas atoms.
- Since they are positively charged, their charge to mass ratio will differ from that of cathode rays.

- **Protons**:
- Protons are positively charged particles with a mass much greater than that of electrons.
- Therefore, their charge to mass ratio is also different from that of cathode rays.

4. **Conclusion**:
- The only option that has the same charge to mass ratio as cathode rays is **beta rays**.

### Final Answer:
Cathode rays have the same charge to mass ratio as **beta rays**.

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