Acircularly polarised beam of light with a vacuum wavelength of 1.55 micro meters is incident on a two cascaded quarter wave-plates, followed by a third unknown wave-plate. the light emerging from the system remains circularly polarised.
find out the jones vector characterizing the state of polarisation of the incident beam of light?

Two 1.20-m nonconducting wires meet at a right angle. one segment carries + 2.50 µc of charge distributed uniformly along its length, and the other carries - 2.50 µc distributed uniformly along it, as shown in fig. 21.50. ( a. find the magnitude and direction of the electric field these wires produce at point p, which is 60.0 cm from each wire. ( b. if an electron is released at p, what are the magnitude and direction of the net force that these wires exert on it?