Deduction u/s sec 80c

How you know that contribution is made out of non taxable income? If you want to claim deduction then you must be having taxable income

Suppose if Mr.A have exempt income of Rs. 50,000 in Cash and also taxable income of Rs. 3,00,000 which is credited in the Bank. Then whether Mr.A can claim Deduction of Rs. 50,000 from the taxable income of Rs. 3,00,000 by depositing the same amount (Rs. 50,000) in PPF a/c. 

Yes practically you can as in ITR you do not disclose cash income or otherwise, and very rare chance that I-T deptt will question this deduction

There is no point in your return where you show that from what source of income are you investing in PPf.

Practically, you invest from the taxable income only.

So, you can claim the deduction of amount invested in PPF upto a maximum limit of Rs. 100000

Deduction can be claimed

Deduction for investment in PPF Account can be claimed...

Deduction can be claimed......

So it seems the Assessee can claim  the deduction irrespective of the source of income from which the contribution to PPF is made....and so even if the assessee deposit any amount in his PPF a/c from his Daughter's / Son's income ...the deduction can be claimed ... Right ?

if the assesee deposit any amount in his PPF a/c from his Daughter's / Son's income ...the deduction can not  be claimed. Only contributions in the tax saving scheme u/s 80 C up to Rs. 1.00 lac in his/children/spouse name out of assesee income which is taxable or exempt is eligible for deduction
 

Deduction can be claimed upto Rs 1 Lakh without doubt.

The Deduction can be claimed, as your AO has no chance of knowing whether you have paid it from Exempt income or Taxable income. And anyways, you did declare your Exempt Income.

P.S.- It is my pure assumption that the income is exempt rather than being undeclared, as it will be wrong in my part to assume the latter...!!

It is very simple and understood that deduction u/s 80C is eligible if invest any saving scheme out of assese income source, which is exmept or taxable income or source of fund i.e loan, gift etc.