The student in a blue windbreaker said he works for the Drug Enforcement Administration while studying for a bachelor's degree at the University of the District of Columbia. He told comedian Bill Cosby, "It just gets scary sometimes."

If he gets his degree, he hopes to get a promotion, the student said, "But if I'm put on a pedestal . . . I'm afraid I'll fall. It's scary."

"What is so scary is that you aren't trying," shot back Cosby, who has a doctorate in education. "This is a time for you to grasp what you can. Go up, man . . . . Don't just stay where you are."

That plea to take advantage of opportunities was the main theme yesterday as Cosby, the Rev. Jesse Jackson, and a phalanx of scholars and celebrities took part in a conference on black education at the University of the District of Columbia.

The two-day conference, which continues today, is sponsored by UDC in cooperation with Push for Excellence, the education offshoot of Operation PUSH, a Chicago-based civil rights and black economic development group that Jackson heads.

Jackson, who has said he might be interested in running as a presidential candidate in 1984, said yesterday that blacks must move on from the "struggle for opportunity" to "a struggle for effort to seize the opportunity."

As about 900 UDC students cheered and applauded, Jackson declared, "You cannot let us down on effort. You have to be prepared . . . . If we use the same energy that is applied to our motor skills to develop our cognitive skills there is nothing to suggest that we blacks cannot be as dominant in science and law and journalism as we are in baseball and basketball."

Cosby also said that black students should stress academics. He suggested they follow the example of Asians, many of whom are immigrants and only form a small minority on most campuses.

"Nobody plays their music," Cosby said. "They don't have a Chinese Day, and they don't complain about not having fraternities. They just get A's on everything. That's why they call them Asians."

In opening the conference UDC president Benjamin H. Alexander said, "I believe in open admissions to college but I do not believe in open graduation.

"Everybody should have an opportunity to seek a higher education," he told the students. "Then it is up to you to succeed or not to succeed. We will not give you degrees."

Since he became UDC's president last summer Alexander has strongly enforced academic suspension policies and moved to reduce remedial work. He has encountered criticism from some faculty members, but yesterday Jackson described Alexander as "a no-nonsense educator" and said, "I endorse that."

"I appreciate an educator who sees you as students and also as children who are unlearned and must learn," Jackson said. "I appreciate a person who risks being unpopular to be prophetic."

As president of Chicago State University before coming to UDC, Alexander hosted a similar education conference for Push for Excellence in 1979. He is a member of the group's board of directors.

Other conference speakers yesterday included Margaret Bush Wilson, chairman of the board of the NAACP, and Mary Berry, a member of the U.S. Civil Rights Commission who was assistant secretary for education under President Carter.