The reported uncertainty of a measurement cannot be greater than the accuracy of the measurement.
In this case the refractive index of glass = 1.5321 +/- 0.00125
Here the measured value = 1.5321 which is reported upto 4 decimal places. However, the uncertainty = 0.00125 has been reported upto 5 decimal places which is inaccurate.
Instead, the refractive index can be reported as: 1.5321 +/- 0.0013
Ans 3)
