The vacuum photocell consists of a glass bulb equipped with two electrical leads. The inner surface of the flask is covered with a thin metal layer with a low work function, which is the cathode. In the flask, helium to increase the sensitivity of the photocell. The light hits the cathode and knocks out the electrons; the anode in the form of a wire loop catches the ejected electrons. A current occurs in the circuit when light hits the photocell cathode.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.