14CFR Part 61 requires that prior to solo flight you must demonstrate acceptable knowledge of the appropriate portions of FAR Parts 61 and 91 to an authorized instructor. This demonstration must include satisfactory performance on a written exam which is administered and graded by the certified flight instructor who endorses your student pilot certificate for solo flight. In addition to questions on the appropriate regulations, the written pre-solo exam must include questions on the flight characteristics and operating limitations for the make and model aircraft to be flown.
Advisory Circular 61-101 also indicates that you must demonstrate adequate knowledge to operate safely during solo flight in your local airspace environment including your departure airport and nearby class B, C, D, and E airspace.
This exam contains a total of 50 questions: 20 general questions, 10 regarding your training aircraft, and 20 regarding your local flight environment. Use of reference materials during this exam such as your training aircraft's Operator's Manual and local aeronautical charts is permitted.