What were the investigations of Hallwachs and Lenard regarding photoel

1.	What were the investigations of Hallwachs and Lenard regarding photoelectric effect?
Answer» Wilhelm Hallwachs (1859-1922), German physicist, found that a metal plate irradiated with ultraviolet radiation lost its charge more rapidly when the plate is negatively charged than when it is neutral or positive. Investigations of photoelectric effect by Phillipp Lenard (1862-1947), German physicist, showed that 1. electron emission occurs only with radiations below a critical wavelength, i.e., above a critical frequency. 2. kinetic energy of the emitted electrons increases as wavelength decreases i.e., frequency increases but is independent of the intensity of radiation which determines the rate of emission of electrons (the number of electrons emitted per unit time).

What were the investigations of Hallwachs and Lenard regarding photoelectric effect?

Answer»

Wilhelm Hallwachs (1859-1922), German physicist, found that a metal plate irradiated with ultraviolet radiation lost its charge more rapidly when the plate is negatively charged than when it is neutral or positive.

Investigations of photoelectric effect by Phillipp Lenard (1862-1947), German physicist, showed that

1. electron emission occurs only with radiations below a critical wavelength, i.e., above a critical frequency.

2. kinetic energy of the emitted electrons increases as wavelength decreases i.e., frequency increases but is independent of the intensity of radiation which determines the rate of emission of electrons (the number of electrons emitted per unit time).

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