Will blacks tune their TV sets to ''The Bobby Jones Gospel Show''? Will they shun CBS and watch ''Black Classic Films''? Can ''The Jazz Hour'' draw an audience that will appeal to national advertisers?
On all counts, Robert Johnson, a former congressional aide and television industry lobbyist, says ''yes.'' Mr. Johnson, now president of Black Entertainment Television (BET), believes black-oriented programming will find a solid audience via cable TV. Two large, mainstream communications companies -- Taft Broadcasting and Tele-Communications Inc. -- agree, and are helping fund BET. Group W, a cable subsidiary of Westinghouse Electric, has been signed to sell and promote the nascent network.
Black Entertainment Television is a good example of how the lines delineating ''black business'' are growing less distinct. Headed by a black, producer of a product aimed at the black community, BET receives both money and important business services from white-run companies.
''My basic philosophy is to make it a successful business with a black conscience,'' Mr. Johnson says. ''We're going to put more black entertainers to work than any other medium, but that can only happen if we're a going concern.''
Now airing three hours a week, BET will begin broadcasting six hours a day, seven days a week in August. It is carried on 852 cable systems, reaching a total of 9.2 million viewers.