The Nobel Prize for Physics was shared yesterday by two Americans and a Briton for work so fundamental in magnetism and electronics that it is only today showing up inside the laboratory, 20 to 30 years after they explained how it works.

At the same time, the Nobel Prize for Chemistry was won by ILya Prigogine, a Belgian, who was born 60 years ago to Russian parents in Moscow during the Bolshevik revolution.

Now professor at the Free University of Brussels and consultant to the University of Texas and General Motors Corp., Prigogine was named winner of the $145,000 prize for his theory of "dissipative structures" that explains how something as ordered as an insect can evolve from a disarray of protein and amino acids.

Named winners of the physics prize were Dr. John H. Van Vleck, 78, who retired eight years ago from the faculty at Harvard University; Dr. Philip W. Anderson, 54, of the Bell Telephone Laboratories in New Jersey, and Sir Neville F. Mott, 72, of Cambridge University in England. They will share equally in the $145,000 prize.

Anderson had been a student of Van Vleck's at Harvard and a decade after leaving Harvard he began a 10-year association with Mott at Cmabridge. Anderson said yesterday that he had brought many of Van Vleck's original ideas with him to Mott, who used them to build a greater understanding of how magnetic forces influence the movement of electrons.

"I think I'm the connection hetween the two," Anderson said yesterday with the kind of humility that was described as typical by his colleagues. "It's almost as if I'm the father and Mott were the son, rather than the other way around . . . It fits with me in the middle."

Anderson said Van Vleck's award was long overdue, a description some colleagues gave to Anderson's award. One colleague said Anderson could easily have shared the award in 1973, when it was given to British physicist Brian Josephson for work Josephson did at the age of 20 under Anderson's tutelage at Cambridge University.

"I'm pleased I'm sharing the award with two men I admire most in the world," Anderson said yesterday. "I couldn't have picked two people I'd rather share any award with . . . "

In announcing the physics award, the Swedish Academy of Sciences in Stockholm emphasized "their work concerning electron-electron interaction and the coupling between the motion of electrons and the atomic nuclei in magnetic and disordered materials . . . "

Physicists interpreted that to mean that Van Vleck shared the award for tis theories 40 years ago that linked magnetism and the mechanics of electron motion for the first time; that Anderson shared it for explaining 16 years ago why metals like iron, nickel and cobalt were magnetic and copper and silver were not; and that Mott shared it for expanding on Anderson's explanation.

"Mott was already interested in developing my explanation when I did it," Anderson said in a telephone interview yesterday. "You might almost say that nobody but Mott recognized its significance when I first proposed it in 1961."

The work of all three men is now recognized in laboratories around the world that are developing "amorphous silicon" semi-conductors, transistors cheaper and easier to make than the conventional devices used in today's computers.

Prigogene was first to explain now molecular order can arise from disorder, how a chemical compound with a formed to a homogenous solution striped red and blue.

"Red is lack of order," one chemist explained. "The stripes are signs of order. I know that's hard to understand but it has revolutionized the study of evolution and the thermodynamics of life."

A concert pianist who changed careers early in life, Prigogene speaks fluent French, Russian and English. Short, stocky and considered vain by many, he is an expert in world traffic problem, which he studies with the same intensity as he does chemistry.

Physicist Van Vleck has long been a consultant to the world's railroads, which stems from his lifelong study of railroad timetables. He memorized Europe's timetables on a trip with his parents when he was 10 years old. Until recently, he advised railroads on how to change their timetables without disrupting service.

"That's the way I was hired by Bell Labs," Anderson recalls yesterday. "He came down from Boston to tell them to hire me, but only if he could ride in the cab of the Phoebe Snow. He was welcome in any train in the world, any time."