Page 42 - Curriculum Visions Dynamic Book

Cadmium and light sensitivity
Cadmium compounds exhibit a range of properties when light shines on them. One of the most commonly
used properties is the change in conductivity that occurs when light falls on cadmium sulphide. Cadmium borate is sensitive to ultraviolet light and is used as phosphor material on TV tubes. Cadmium sulphide can also be used as a material that will generate electricity – a solar cell. Most exposure meters
in use are photoelectric instruments having either cadmium sulphide or selenium photoelectric cells as light- sensitive elements.
Photovoltaic cells
A device that generates electricity when light falls on it is called a photovoltaic or solar cell.
A range of materials can be used for photovoltaic cells. Usually, two materials are put in contact, the most common being silicon, gallium arsenide, cadmium sulphide and cadmium telluride.
Solar cells made of cadmium sulphide can be made thinner and lighter than silicon cells, but they have a maximum efficiency of about 6%, as opposed to over 14% for silicon cells.
 Cadmium compounds are among a range of substances that fluoresce under ultraviolet light. These substances are called fluorescent phosphors, and they make the light-emitting coatings on cathode ray tubes and fluorescent tubes.
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