will calcium show good photoelectric emission. if yes then why?
Answers
Answer:
The photoelectric effect
The photoelectric effect is the process whereby an electron is emitted by a substance when light shines on it.
Einstein received the 1921 Nobel Prize for his contribution to understanding the photoelectric effect. His explanation wasn't very popular and took a while to be accepted, in fact, some scientists at the time felt that is was a big mistake.
In the motivation letter for Einstein to be accepted into the Prussian Academy of Science it was specifically mentioned as a mistake:
In sum, one can say that there is hardly one among the great problems in which modern physics is so rich to which Einstein has not made a remarkable contribution. That he may sometimes have missed the targeting his speculations, as, for example, in his hypothesis of light-quanta, cannot really be held too much against him, for it is not possible to introduce really new ideas even in the most exact sciences without sometimes taking a risk - A. Pais, “Subtle is the Lord: The Science and the Life of Albert Einstein,” New York: Oxford University Press, 1982, p. 382
Implications of Einstein's model (ESCQM)
Einstein's model is consistent with the observation that the electrons were emitted immediately when light was shone on the metal and that the intensity of the light made no difference to the maximum kinetic energy of the emitted electrons.
The energy needed to knock an electron out of the substance is called the work function (symbol W0) of the substance. This is a characteristic of the substance. If the energy of the photon is less than the work function then no electron can be emitted, no matter how many photons strike the substance. We know that the frequency of light is related to the energy, that is why there is a minimum frequency of light that can eject electrons. This minimum frequency we call the cut-off frequency, f0. For a specific colour of light (i.e. a certain frequency or wavelength), the energy of the photons is given by E=hf=
hc
λ
, where h is Planck's constant. This tells us that the W0=hf0 .
Work function
The minimum energy needed to knock an electron out of a metal is called the work