Question

The detector in photo-phone is made up of?

Answer 1

Answer:

selenium cell

Explanation:

Answer 2

Answer:

simple selenium cell

Explanation:

• The photophone can be defined as a telecommunications device that enables transmission of speech on a beam of light.
• it had been invented jointly by Alexander Graham Bell and his assistant.
• The photophone was the same as the more recent telephone, except that it used modulated light as a way of wireless transmission while the telephone relied on modulated electricity carried over a conductive wire circuit.
• in its ultimate electronic form, the photophone receiver used a straightforward selenium cell photodetector at the main target of a parabolic mirror.
• Selenium enhances and stretches the tonal range of black-and-white photographic images and improves the permanence and long lastingness of prints.

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