The constancy of e/m ratio for electron shows that

Options

A. Electron's mass is `1//1837^(th)` of the mass of proton
B. Electrons are universal particles of all matter
C. Electrons are produced in discharge tubes only
D. None of the above

Answer

To solve the question regarding the constancy of the e/m ratio for electrons, we will analyze the options provided and derive the correct conclusion step by step.

### Step-by-Step Solution:

1. **Understanding the e/m Ratio**:
The e/m ratio refers to the charge-to-mass ratio of an electron. It is a constant value that indicates how much charge an electron has relative to its mass.

2. **Mass of Electron and Proton**:
- The mass of an electron (m_e) is approximately \(9.1 \times 10^{-31}\) kg.
- The mass of a proton (m_p) is approximately \(1.67 \times 10^{-27}\) kg.

3. **Calculating the Ratio**:
To find the ratio of the mass of an electron to the mass of a proton:
\[ \frac{m_e}{m_p} = \frac{9.1 \times 10^{-31}}{1.67 \times 10^{-27}} \]
Performing the calculation:
\[ \frac{m_e}{m_p} \approx \frac{9.1}{1.67} \times 10^{-4} \approx 0.00545 \times 10^{-4} \approx 1/1837 \]
This shows that the mass of an electron is approximately \(1/1837\) of the mass of a proton.

4. **Analyzing the Options**:
- **Option 1**: "Electrons mass is \(1/1837\) of the mass of proton" - This statement is correct based on our calculation.
- **Option 2**: "Electrons are universal particles of all matters" - This statement is also correct as electrons are fundamental components of all atoms.
- **Option 3**: "Electrons are produced in a discharge tube only" - This statement is incorrect because electrons can be produced in various processes, not just in discharge tubes.
- **Option 4**: "None of the above" - This is incorrect since we have found correct statements in options 1 and 2.

5. **Conclusion**:
Based on the analysis, the constancy of the e/m ratio for electrons indicates that electrons are universal particles of all matter, and it also confirms that the mass of an electron is significantly smaller than that of a proton.

### Final Answer:
The constancy of the e/m ratio for electrons shows that **electrons are universal particles of all matter**.

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