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

CONCEPT :

• Davison Germer experiment was conducted in 1927 to study the wave nature of the electron.
• The electrons are emitted by an electron gun and are accelerated by applying a suitable potential difference between anode and cathode.
• The finely collimated beam is directed towards the Ni crystal.
• The scattered electrons are collected using a movable detector and a graph is plotted between applied potential and angle of reflection.
• Analysis of those graphs showed the wave nature of the electron.

EXPLANATION:

​The energy of an electron accelerated through a potential V₀ is given by

⇒ E = eV₀ 

Where e = Charge on an electron, V₀ = Applied potential

The energy of an accelerated electron through a potential V₀ is purely kinetic in nature. Therefore,

\(⇒ eV_0 = \frac{1}{2}mV^{2}\)

From the above equation, the relationship between V₀ and V² can be written as

⇒ V₀ ∝ V²

From the above equation, it is clear that the applied potential is directly proportional to the velocity of the emitted electron.

Hence the velocity of electrons emitted from the electron gun can be increased by increasing the potential difference between the anode and filament. Therefore option 2 is correct.