Can i use a lithium battery instead of alkaline for coolpix L120 camera

Yes, you can as long as they are AA battery type. The lithium battery has rechargeable battery ( lithium-ion battery ) or metallic lithium used in the non-rechargeable lithium battery.

  Thank u.. is it necessary to check voltage/Ampere range on Lithium AA Battery for Coolpix L120 camera as it will be available in many ranges..? n suggest me name (Product/Brand) for best lithium AA battery for my Camera..:-

As long as any of them have the1.5 volts then it will be fine. Buy the good brands like Energizer, Duracell, Philips, Sanyo, etc. For example http://www.amazon.com/s/ref=nb_sb_ss_i_0_20?url=search-...

If you want go green to get the rechargeable batteries (NiMH), because NiMH batteries do not have a "memory effect". And you should get the one has high capacity like over 2400/2500mAh.