Question For (i) I assumed that the light was plainly polarised as there is only a difference in amplitude For (ii) There is a negative sign infront of the amplitude which I ignored as it doesn't change the polarisation but one is cos and the other is sin, so there is a phase shift of pi/2 and hence the light is lefty circularly polarised? For (iii) There is a cos so a phase change of pi/2 but also another change of pi/2 so again the light would be plainly polarised?? Any help with this would be great as it is for my exam!:) I should also say I don't know how to sketch the tip of the resultant vector not sure what this means!! Thanks a bunch!!!