Penalty for non-payment of tax.

If any assessee fails, without, reasonable cause to make payment of any amount of tax within the time specified in the notice of demand, the assessing authority may, after giving him a reasonable opportunity of making his representation, impose upon him a penalty which shall not be less than twenty-five per cent but not exceeding fifty percent of the amount of tax due. This penalty shall be in addition to the interest payable under sub-section (1) or sub-section (2) of section 11.