When measuring a refractive index, what should you do if
(a) no dividing line between light and dark areas can be observed through the eyepiece?
(b) the dividing line can be seen, but it is fringed with color?

Question

Quizplus · Accepted Answer

The Answer is (a) Either (1) use the fine or the coarse adjustment control knob on the refractometer, the knobs that control the refractive index setting of the instrument, or, if (1) does not work, (2) place more compound on the prism.
(b) Adjust the dispersion correction knob.

When Measuring a Refractive Index, What Should You Do If