Usually you have a RNase step to digest your RNAs, but you can try to do a migration on a 1% agarose gel, 5-10 minutes with high exposure, if you have relatively short weight bands below your DNA it's probably RNA or Fragmented DNA.

you will know if you have rna contamination if the OD260/280 is greater than 2. this usually indicates na as the dna value should be1.8-2. There are many dna preparation methods .Which one are you using will make it easier to answer the question which reagent excludes the RNA

RNA is very fragile. Each step of its extraction needs more care. Every thing from clothes, glooves and the utensils must be sterilized and well as the buffer must contain RNAase inhibitor.Therefore you can hardly find any RNA. Secondly the buffer that you use for extraction is differ from the DNA extraction. To extract DNA is very easy and you can extract using CTAB or any buffer. Secondly if you are talking about the quantity of RNA at final solution I agree with Dr. Paul Rutland. For more: https://juniperpublishers.com/artoaj/pdf/ARTOAJ.MS.ID.555717.pdf

RNase treatment

Dear Mayilvanan, usually you have the opposite problem: RNA is a single strand nuclic acid and for this feature it's very fragile. Moreover RNA is subjected to degradation by RNase that are really resistent digestion enymes that work in a large pH range and very difficult to inhibit even in autoclave. I think that if you don't use RNase free plastics and you don't use DEPC you should be quite serene to don't have RNA contamination. Anyway you can use RNase A (Qiagen for instance) to avoid all RNA contamination problems and then check that your extractions have a ratio 260/280 between 1,5 - 1,7, if more there could be contaminations.

Good luck