Me! what year or century was max planck model adapted?

Planck announced his findings in 1900, and in 1905, Albert Einstein used Planck's quantum theory to describe the particle properties of light. Einstein demonstrated that electromagnetic radiation, including light, has the characteristics of both a wave and, consistent with Planck's theory, a particle. These particles were later called photons. In 1913, Niels Bohr used Planck's theories to develop a new and more accurate model of the atom.

Max Planck was born in Kiel, Germany, on April 23, 1858, and was considering becoming a professional pianist before a teacher turned his attention to science. Planck went on to receive degrees from the University of Berlin and the University of Munich.

After spending four years as an associate professor of theoretical physics at Kiel University, Planck moved to the University of Berlin, where he became a full professor in 1892.

Planck's passion was thermodynamics. While researching black-body radiation, he too kept running into the same problem as other scientists. Classical physics could not explain the results he was finding.

In 1900, 42-year-old Planck discovered an equation that explained the results of these tests: E=Nhf, with E=energy, N=integer, h=constant, f=frequency. In determining this equation, Planck came up with the constant (h), which is now known as "Planck's constant."

The amazing part of Planck's discovery was that energy, which appears to be emitted in wavelengths, is actually discharged in small packets he called "quanta".

This new theory of energy revolutionized physics and opened the way for Albert Einstein's theory of relativity.