Time management is very much important in IIT JAM. The eduncle test series for IIT JAM Mathematical Statistics helped me a lot in this portion. I am very thankful to the test series I bought from eduncle.
Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
Rahul kumar
Answer: 90 degrees Any anisotropic mineral appear extinct four time during a 360° rotation. If a mineral is extinct at 30° then again after 90° rotation, the mineral will appear extinct.