if two child of one family both will eligible jagananna vidya deevena ?

Yes, They have not mentioned anywhere that two kids of the same family can't avail it. The scheme was based on right of education to everyone.

Only the families

1. whose annual income is less than Rs. 2.5 lakh .
2. having less wet 10 acres or dry 25 acres or 25 acres wet and dry.
3. No member should be Government employee or pensioner (all sanitary workers are exempted.).
4. Family should not own 4 wheeler (Taxi, Auto, Tractors Exempted)
5. No family member should pay income tax.
6. In municipal areas owning less than 1500 sft of built up area

Are eligible

Official website link

https://navasakam.ap.gov.in/

Hope this helps!