How to Calculate the Unknown Parameter Using the Einstein’s formula for the Photoelectric Effect – Part 1

The photoelectric effect is the emission of electrons (called photoelectrons) from a material caused by electromagnetic radiation, viz., ultraviolet light.


The effect is not only studied in condensed matter physics, solid state, and quantum chemistry to draw inferences about the properties of atoms, molecules and solids but also has profound applications in electronic devices specialized for light detection and precisely timed electron emission.

Einstein's formula explained the photoelectric effect, and had far-reaching consequences in the development of quantum mechanics.

Question:

Following results are observed when Sodium metal is irradiated with different wavelengths. Calculate the threshold wavelength.

l (nm)

500

450

400

v × 10–5 (cm s–1)

2.55

4.35

5.35

Click to enlarge the image

Solution:



Click to enlarge the image

Kmax = Maximum kinetic energy, h = Planck constant, n = Frequency, n0 = Threshold frequency, l0 = Threshold wavelength

Piqued by the photoelectric effect❓ Let Chemaficionado know at mychemistryhomework@gmail.com❗

References:

(1)    Photoelectric effect. Wikipedia. https://en.wikipedia.org/wiki/Photoelectric_effect.

‌(2)    Ncert. Chemistry : Textbook for Class XI - Part.I; National Council Of Educational Research And Training: New Delhi.

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