Legal Question in Criminal Law in India

Your facts are not clear. However for answer to your question, first, my understanding of the fact:

Either Partner 1 or Partner 2 have the signing authority.

Also Partner 2 has a power of attorney from that firm.

Partner 1 has signed the cheque for 5 Lacs without notice to partner 2.

there is nothing wrong done by the partner 1 under the partnership act unless partnership deed provides to the contrary. Mere fact that partner 2 has the power of attorney that by itself does not mean that partner 1 cannot sign a cheque without notice because partner 1, otherwise is entitled to sign on the basis of Either/Or.