From Wikipedia, the free encyclopedia. Permanent Account Number (PAN) is a code that acts as identification of Indians, especially those who pay Income Tax. It is a unique, 10-character alpha-numeric identifier, issued to all judicial entities identifiable under the Indian Income Tax Act 1961. IT PAN card is issued under Section 139A of the Income Tax Act. 2  The PAN structure is as follows: AAAPL1234C: First five characters are letters, next four numerals, last character letter. 3  The first three letters are sequence of alphabets from AAA to ZZZ. 4  The fourth character informs about the type of holder of the card.
The scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry is commonly based on empirical or measurable evidence subject to specific principles of reasoning.
For the study of the development of science, see History of science. Historical method comprises the techniques and guidelines by which historians use primary sources and other evidence, including the evidence of archaeology, to research and then to write histories in the form of accounts of the past.