What is difference between financial ac and cost ac?

Answer 1

I believe the intended question was "What is the difference between financial accounting and cost accounting?" The question makes no sense in the categories of electrical and Electronics Engineering. And so I have added the category of Business to the topic.

The difference between the two types of accounting:
Financial Accounting's goal is for preparing financial statements for use by parties outside of a company's management. The statements that are prepared for stockholders and investors, regulators, analysts and other outside parties present the external view of a company according to established and accepted standards. One of these is known as GAAP, Generally Accepted Accounting Procedures.
Cost Accounting is subcategory of Managerial Accounting which deals with the internal management of the company. Each company's managers may have different needs and so each company may have somewhat different practices for Management Accounting. Cost Accounting deals with the planning and tracking of the costs of operating the company. The needs will vary between kinds of companies. A manufacturer must deal with costs of raw materials and parts, whereas a bank does not need to deal with costs at such a granular level.