Set as children's homework for Key Stage 2
2007-01-17 01:51:34 · 5 answers · asked by florenceflossie 1 in Science & Mathematics ➔ Physics
Light sensors contain things called photovoltaic cells that convert light energy into electric energy. The amount of electric energy may be small, but enough to send a signal to whatever piece of kit to tell that light is shining on the sensor.
2007-01-17 01:55:59 · answer #1 · answered by k² 6 · 2⤊ 0⤋
Basically two types of light sensor.
1. Light on the sensor element produces a voltage.
2. Light on a sensor changes the electrical resistance of the sensor element.
2007-01-17 10:01:14 · answer #2 · answered by efes_haze 5 · 0⤊ 0⤋
Light sensors contain photo-voltaic cells. On light impinging on these cells voltages are induced which drive further circuitry to get the desired information and display.
2007-01-17 10:02:49 · answer #3 · answered by openpsychy 6 · 0⤊ 0⤋
light falls onto the panel and knocks electrons off (that's how solar panels work - called the photoelectric effect) and this tiny current of electrons trips a switch and allows the light bulb or whatever to come on. when the light is blocked, the current stops and the switch turns off.
2007-01-17 09:56:40 · answer #4 · answered by phedro 4 · 0⤊ 0⤋
One of the properties of silicon is that when light hits it, it causes electrons to flow on its surface. Presto, electricity.
2007-01-17 10:38:16 · answer #5 · answered by Anonymous · 0⤊ 0⤋