0 an instrument for measuring the intensity of light, usually by comparing the light source being measured with a source that has standard characteristics -- quang kế
When a professional photographer sets up a shoot, he or she will use a photometer to measure light levels on and around the subject being shot.
If the sample volumes are large enough to use microplates or cuvettes, the dye-loaded samples can also be quantified with a fluorescence photometer.
Although the selenium cell photometer was proving successful, it was difficult to use and not very sensitive.
With a new design of photometer, he was able to measure the exceptionally faint stars in these clusters.
Initial light output is measured with an integrating sphere photometer, 30 seconds after the light is switched on with fresh (or newly charged) batteries.
Other general purpose light power measuring devices are usually called radiometers, photometers, laser power meters, light meters or lux meters.
The time of day, the circadian phase, is signalled to the pineal gland, the bodys photometer, by the suprachiasmatic nucleus.
A multiangle absorption photometer takes into account both transmitted and reflected light.
O and two fast photometers are used to correct star scintillation perturbations and to determine high vertical resolution temperature profiles.
