Dual Nature of Radiation and Matter

Thermionic emission, Field emission, Photoelectric emission

The three main types of electron emission are: (1) Thermionic emission - by heating, (2) Field emission - by applying strong electric field, and (3) Photoelectric emission - by illuminating with light of suitable frequency.

Current increases

Photoelectric current is directly proportional to the intensity of incident light. Higher intensity means more photons per second, leading to more photoelectrons being emitted per second, thus increasing the current.

It is the minimum frequency for photoelectric emission, It depends on the nature of the metal, Below this frequency, no emission occurs regardless of intensity

Threshold frequency (ν₀) is the minimum frequency required for photoelectric emission. It depends on the work function and hence the nature of the metal. Below this frequency, no photoelectric emission occurs regardless of intensity.

the minimum negative potential at which photocurrent just becomes zero

The stopping potential is defined as the minimum negative (retarding) potential given to the collector plate for which the photocurrent stops or becomes zero. It is related to the maximum kinetic energy of the photoelectrons by K_max = eV_0. So it is not the accelerating potential or the threshold for emission itself.