For 10 points, name these devices that give an electrical output in response to light.
Invented in 1900 by Johann Elster and Hans Geitel, the voltage applied by the conductive variety varies with intensity while the multiplier variety uses an electric field to attract electrons to the dynode, thus converting into a measurable electric current. In this device, an electron tube with a photosensitive cathode emits electrons when illuminated, which an anode collects with the current being proportional to the intensity of the light. For 10 points, name these devices that give an electrical output in response to light.
Invented in 1900 by Johann Elster and Hans Geitel, the voltage applied by the conductive variety varies with intensity while the multiplier variety uses an electric field to attract electrons to the dynode, thus converting into a measurable electric current.
{Photocell} or {photoelectric cell} or {electric eye} or {photo tube}