I want to know what is meant by spectral bandwidth in case of a UV VIS Spectrophotometer. Does it have any relation to the Slit width? How can bandwidth be changed or controlled?
Your UV/Vis Spectrophotometer has a monochromator (grating or prism) that disperses the light from the light source towards a small opening (a slit) that let's through a narrow spectrum of wavelengths (narrow spectrum, but spectrum nevertheless), centered at the selected wavelength. This spectrum contains a gaussian distribution of wavelengths and the width of this distribution (at half height) is called spectral bandwidth...
Slit width is the physical size of the opening (slit) that lets the light through to the sample. Slit width hence also determines the bandwidth. Depending on the spectrophotometer make, mode and prize you might be able to adjust the slit width... Look at the specs of your spectophotometer.
I'm not sure what the functional relationship between bandwidth and slit width is (it depends somehow on the geometry of the apparatus) but by changing the slit width, you also control the bandwidth...
Thank you very much.