Which of the following statements are true regarding Davisson - Germer experimental setup?

(i) Electrostatic particle accelerators are used to accelerates the electrons

(ii) Electron beam is fired from the electron gun to nickel crystal.

(iii) Detector used to capture the electrons.

CONCEPT:

Davisson and Germer Experiment:

• In 1927, and Germer designed an experiment to study the wave properties of electrons.
• Here the electrons emitted by the hot filament of an electron gun are accelerated by applying a suitable potential difference ‘V’ between the cathode and anode.
• The finely collimated beam of electrons from the electron gun is directed against the face of Ni crystal. The crystal is capable of rotation about an axis perpendicular to the plane of the paper.
• The electrons, scattered in different directions by the atoms of Ni crystal, are received by a movable detector which is just an electron collector.
• Thus we measure scattered electron intensity as a function of the scattering angle Φ, the angle between the incidence and the scattered electron beam. 

EXPLANATION:

• Electron gun emits electrons via thermionic emission.
• Two opposite charged plates are used to accelerate the electron called as electrostatic particle accelerators. Therefore statement 1 is correct.
• Nickel crystal used as target and electron beam is fired on Nickel crystal. Therefore statement 2 is correct.
• Detector is used to capture the scattered electron beam. Therefore statement 3 is correct.