Why the photoelectric cell is also called an elecric eye?

Nitrolim is also called as-

Alburnum is also called as

Photoelectric effect When light of sufficiently small wavelength is incident on a metal cathode, it may emit electsons called photoelectrons. This is called photoelectric effect. Above threshold frequency, the stopping potential and hence the energy of the photoelectrons is directly proportional to the frequency. In the given figure, we see the variation of stopping potential with the frquency of incident radiation for three metals A, B and C Which of these metals A, B or C are suitable for photoelectric cell?

Sodium carbonate is also called

Galvanic cells are also named as