The carrier frequencies of two narrow-band signals launched at the same instant of time to travel as free (unguided) waves along the same path in a plasma medium with concentration of free electrons of N = 10^7m^-3, are f_1 = 40 kHz and f_2 = 50 kHz, respectively (a) What is the time lag between the signals as they are received on the other end of the path, if its length is l = 50m ? (b) Repeat (a) but for the carrier frequencies of signals changed to f_1 = 40 MHz and f_2 = 50 MHz, respectively.
