আলোকীয় পৃষ্ঠআলোকীয় সমতল
আলোকীয় বৰ্ণালীমেতা (Assamese)
1. An optical spectrometer (spectrophotometer, spectrograph or spectroscope) is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in... from wikipedia.org