(1) Where in respect of any tax period of an assessment year-

(i) any dealer has not submitted tax return within the time prescribed or within the time extended by the assessing authority, or if tax return has been submitted without payment of tax shown payable in such return; or

(ii) preliminary examination of tax return, by the assessing authority, reveals that computations shown in the tax return are wrong or amount of input tax credit claimed or tax payable shown is incorrect; or

(iii) on the basis of material available on records with the assessing authority, it appears to the assessing authority that the turnover of sales or purchases or both, disclosed by the dealer is not worthy of credence; the assessing authority may, after making such inquiry as it may deem fit and after giving a reasonable opportunity of being heard to the dealer, determine -

(i) to the best of its judgment the turnover, amount of tax payable and amount of input tax credit admissible, where the dealer has not submitted tax return or if the tax return has been submitted, the assessing authority is of the opinion that turnover disclosed by the dealer in such return is not worthy of credence; or

(ii) the amount of tax payable and amount of input tax credit admissible, in any other case, by passing a provisional order of assessment for such tax period.

(3) Amount of tax, assessed under sub-section (1) in excess of the amount of tax deposited by the dealer, shall be paid by the dealer in the prescribed manner and within a period of thirty days from the date of service of the order of assessment and prescribed notice of demand on him.