Consider a silver target in coolidge tube to produce x-rays. The accelerating potential is 31 kV. `E_(K)=25.51 KeV, E_(L)=3.5 1 KeV. "If" lambda_(K alpha)-lambda_("min")` is approximately8N pm(in pm), where N is an integer find N. Round off to nearest integer.
(Take : hc = 1240 e V nm)