56. The irradiation of a metal monochromatic electromagnetic radiation with a wavelength λ = 248 nm, the photocurrent is stopped for some retarding voltage U1. Increasing the emission wavelength of 1.25 times, the delay voltage was less than 1 V. Determine according to Planck's constant experiment.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)