About Authors
N.K. Sehgal is a retired Associate Professor in Physics who taught Physics to undergraduate students at “Hans Raj College, University of Delhi”, Delhi for nearly 44 years. He is a first class first in M.Sc. (Physics) and is a winner of “Dr K.S. Krishnan Gold Medal”. He is the co-author of a number of textbooks for undergraduate, senior school and secondary school students. He has been a “resource person” for teachers training workshops and other academic works for a number of organizations.