Question

Which metal has the maximum work function related to photoelectric effect?

• A. Platinum
• B. Caesium
• C. Sodium
• D. Calcium

Answer 1

Answer:

A. Platinum

• The work function ($\Phi$) of a metal is defined as the minimum amount of energy required to remove an electron from the surface of a metal to a point just outside the metal surface.

• It is typically measured in electronvolts (eV).

• The value of the work function depends on the material's surface properties, electronic structure, and the nature of the chemical bonds within the crystal lattice.

• Platinum (Pt) has the highest work function among common metals, typically ranging from approximately 5.6 eV to 5.9 eV.

• Due to its high work function, platinum is highly resistant to electron emission, making it a stable choice for electrodes in various electrochemical applications.

• Conversely, alkali metals like Cesium (Cs) possess the lowest work function (approximately 2.14 eV), making them highly efficient for photoelectric emission even under visible light.

• The photoelectric effect occurs only when the energy of incident photons ($E = h\nu$) is greater than or equal to the work function ($\Phi$) of the metal surface.