In the Davisson and Germer experiment, the velocity of electron of electrons emitted from the electron gun can be increased by

Options

A. Decreasing the potential difference between the anode and filament
B. Increasing the potential difference between the anoda and filament
C. Increasing the filament current
D. Decreasing the filament current

Answer

To solve the question regarding how to increase the velocity of electrons emitted from the electron gun in the Davisson and Germer experiment, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of the Electron Gun**: The electron gun is responsible for emitting electrons and can control their energy and velocity.

2. **Relate Potential Difference to Electron Energy**: The energy (E) of an electron emitted from the electron gun can be expressed in terms of the potential difference (V) applied across the gun. The relationship is given by the equation:
\[ E = eV \]
where \( e \) is the charge of the electron.

3. **Kinetic Energy of Electrons**: The kinetic energy (KE) of the emitted electrons can also be expressed as:
\[ KE = \frac{1}{2} mv^2 \]
where \( m \) is the mass of the electron and \( v \) is its velocity.

4. **Equate the Two Energy Expressions**: Since the energy provided by the potential difference is converted into kinetic energy, we can set the two expressions equal to each other:
\[ eV = \frac{1}{2} mv^2 \]

5. **Solve for Velocity**: Rearranging the equation to solve for velocity \( v \):
\[ v = \sqrt{\frac{2eV}{m}} \]
This shows that the velocity of the electrons is proportional to the square root of the potential difference \( V \).

6. **Conclusion**: To increase the velocity of the emitted electrons, we need to increase the potential difference \( V \) applied across the electron gun. Thus, the correct approach is to increase the potential difference between the anode and filament.

### Final Answer:
The velocity of electrons emitted from the electron gun in the Davisson and Germer experiment can be increased by **increasing the potential difference between the anode and the filament**.

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