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)
Ruby negi
we know resolving power of telescope=diameter/(1.22*wavelength)... using this you canfind diameter for every wavelength and then check which diameter is greater and which is smaller