Photoelectric effect

Question 1

What did Max Plank introduce in 1900

Question 2

What did Einstein recognise in 1905

Question 3

Formulae for energy of a photon

Answer 3

E=hf
E=hc/lambda

Question 4

Definition of an electronvolt

Answer 4

One electronvolt is the energy of an electron accelerated by a potential difference of 1 volt

Question 5

converting 1 eV to joules

Answer 5

1eV=1.6x10^-19 J

Question 6

Using the photoelectric effect to explain the gold leaf experiment (check if this will be examined)

Answer 6

The ultraviolet causes electrons to be emitted from the zinc plate. If the plate is charged positively, the electrons are attracted back again. If the plate is charged negatively the emitted electron are repelled and lost from the plate forever.

Question 7

Definition of the photoelectric effect

Answer 7

when light or ultraviolet radiation of short enough wavelength falls on a surface, electrons are emitted from the surface.

Question 8

Einstein’s photoelectric equation and definition

Answer 8

Ek max= hf-(phi)
where Ek max is the maximum energy that a photo-electron can have once it has used some of the photon energy to leave the metal surface.
hf is the energy of the photon
(phi) is the minimum energy an electron needs to leave the surface.