The Bonds shall bear interest payable annually or semi-annually, from their date, at the rate of not more than 7% per annum. The Bonds shall be serial bonds and be dated, issued and sold by the Governor, from time to time, in such amounts as may be necessary to provide funds for the specific purposes contemplated by Section 2 of this Act. Each Bond shall be in the denomination of $5,000 or some multiple thereof, and shall be made payable within not more than 30 years from its date as the Governor shall determine. These Bonds shall be signed by the Governor and attested by the Secretary of State under the printed facsimile seal of the State and countersigned by the State Treasurer by his manual signature or by his duly authorized deputy. The signatures of the Governor and the Secretary of State may be printed facsimile signatures. Interest coupons with printed facsimile signatures of the Governor, Secretary of State and State Treasurer may be attached to the Bonds. The fact that an officer whose signature or facsimile thereof appears on a Bond or interest coupon no longer holds such office at the time the Bond or coupon is delivered shall not invalidate such Bond or interest coupon.