Which postulate of the cathode ray tube experiment shows that these rays comprise of negatively charged particles?

Explanation

To answer the question about which postulate of the cathode ray tube experiment shows that cathode rays comprise negatively charged particles, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Cathode Rays**:
- Cathode rays are streams of electrons emitted from the cathode (negative electrode) in a vacuum tube.

2. **Application of Electric Field**:
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