Such revenue bonds shall bear interest at not more than twelve percent per annum, payable at such times, and shall mature at such time or times as may be determined by ordinance. Such bonds may be made redeemable before maturity at the option of the municipality, to be exercised by said board, at not more than the par value thereof and a premium of five percent, under such terms and conditions as may be fixed by the ordinance authorizing the issuance of the bonds. The principal and interest of the bonds may be made payable in any lawful medium. Said ordinance shall determine the form of the bonds, either coupon or registered, shall set forth any registration and conversion privileges, and shall fix the denomination or denominations of such bonds and the place or places of payment of the principal and interest thereof, which may be at any bank or trust company within or without the state. The bonds shall contain a statement on their face that the municipality shall not be obligated to pay the same or the interest thereon except from the special fund provided from the net revenues of the works. All such bonds shall be, and shall have and are hereby declared to have all the qualities and incidents of, negotiable instruments under the Uniform Commercial Code of the state. Said bonds shall be exempt from all taxation, state, county and municipal. Such bonds shall be executed by the proper legally constituted authorities of the municipality, and be sealed with the corporate seal of the municipality, and in case any of the officers whose signatures appear on the bonds or coupons shall cease to be such officers, before delivery of such bonds, such signatures shall nevertheless be valid and sufficient for all purposes the same as if they had remained in office until such delivery. Such bonds shall be sold at a price not lower than a price, which when computed upon standard tables of bond values, will show a net return of not more than thirteen percent per annum to the purchaser upon the amount paid therefor, and the proceeds derived therefrom shall be used exclusively for the purposes for which said bonds are issued and same may be sold at one time or in parcels as funds are needed. Any surplus of bond proceeds over and above the cost of the works shall be paid into the sinking fund hereinafter provided. If the proceeds of the bonds, by error of calculation or otherwise, shall be less than the cost of the works, additional bonds may in like manner be issued to provide the amount of such deficit and, unless otherwise provided in said ordinance authorizing the issuance of the bonds first issued or in the trust indenture hereinafter authorized, shall be deemed to be of the same issue and shall be entitled to payment without preference or priority of the bonds first issued. Prior to the preparation of the definitive bonds, temporary bonds may under like restrictions be issued with or without coupons, exchangeable for definitive bonds upon the issuance of the latter.