Which of the following are the properties of an electron?
1. Electron is a constituent of cathode ray
2. Electron is a nagatively charged particle
3. The mass of the electron is equal to the mass of the proton
4. Electron is deflected by tyhe electric field but not by magnetic field
Select the correct answer using the code given below:

Options

A. 1 and 2 only
B. 1,2 and 3
C. 3 and 4
D. 1 and 4

Explanation

To determine the properties of an electron, we will analyze each statement provided in the question:

1. **Electron is a constituent of cathode ray**:
- This statement is **correct**. Electrons are indeed the particles that make up cathode rays. When a cathode is heated in a vacuum tube, it emits electrons, which travel towards the anode.

2. **Electron is a negatively charged particle**:
- This statement is also **correct**. By definition, an electron carries a negative charge.

3. **The mass of the electron is equal to the mass of the proton**:
- This statement is **incorrect**. The mass of an electron is approximately 1/1836 times the mass of a proton. Therefore, they are not equal.

4. **Electron is deflected by the electric field but not by the magnetic field**:
- This statement is **incorrect**. An electron is deflected by both electric and magnetic fields. The deflection in a magnetic field occurs due to the Lorentz force acting on the charged particle.

Now, let's summarize the correct properties of an electron based on the analysis above:

- **Correct Statements**:
- 1. Electron is a constituent of cathode ray (True)
- 2. Electron is a negatively charged particle (True)

- **Incorrect Statements**:
- 3. The mass of the electron is equal to the mass of the proton (False)
- 4. Electron is deflected by the electric field but not by the magnetic field (False)

Thus, the correct answer is **1 and 2 only**.