Tbill & gsec

• Bonds and SDL: Interest credited to the bank account is considered income from other sources, and taxes have to be paid according to the income tax slab. Appreciation in bond prices is considered capital gains, and Long Term Capital Gains (LTCG) are 10% flat. Short Term Capital Gains (STCG) are as per the applicable slab rate. There is no Tax-deducted-at-source (TDS) for the interest payments received for G-secs.
• T-bills: T-bill are bought at a discount and sold at par. The appreciation is considered as STCG and taxed as per the applicable slab rate.

so if a person has invested in tbills since it stcg its at 15% tax right? and we use itr 2? 

15% slab is u/s. 111A is for equity based units.

Not for such ST cap gain. Here it is taxed as per slab rate.

Yes, ITR 2 can be used for its declaration.

if i have no gains from shares but income from tbills , i can use itr 1 then and show the income from t bills as income from other sources?

Yes, possible if the amount is not very big.

if i use it2 then where m i supposed to declare this income ?

Short term CG u/s. 111 IT act, in Schedule CG.