Any bonds issued under the provisions of this Sub-part shall be authorized by ordinance or resolution of the governing authority of the municipality, which ordinance or resolution shall authorize the issuance of the bonds at such rate of interest as may be bid for the same in response to the advertisements hereinafter required.  The ordinance or resolution shall not be voted unless notice of the intention to introduce the same has been given in a newspaper published in the municipality three times in ten days preceding introduction thereof, and shall be signed by the mayor or acting mayor of the municipality, in the name and under the seal of the municipality.  The payment of the bonds shall be secured by an act of mortgage on the lands, buildings, machinery and equipment and by a pledge of the income and revenues of such public utility, or by either such mortgage or such pledge, as the governing authority of the municipality may determine and provide in the ordinance or resolution authorizing the issuance of the bonds.