# Consider a long straight wire of cross-sectional area A carrying a current i.Let there be n free electrons per unit volume.An observer places himself on a trolley moving in the opp. direction to the current with a speed v=i/(nAe) and separated from the wire by a distance r.the magnetic field as seen by the observer is very nearly (a) µo i/2pr (b) µo i/pr (c) µo i/2pr (d) 0 a steady electric curr.is flowing thru a cylindrical conmductor . (a)the electric field at the axis of the conductor is zero (b)The magnetic field at the axis of the conductor is zero. (c)The electric field at the vicinity of the conductor is zero. (d)The magnetic field at the vicinity of the conductor is zero. let E and B (vectors) denote electric and magnetic fields in a frame S and E’ and B’ (vectors) denote electric and magnetic fields in a frame S’ moving with a velocity v w.r.t S.2 of the following equations r wrong. (a) B’y=By+vEz/c2 (b)E’y=Ey-vBz/c2 (c) B’y=By+vEz (d) E’y=Ey+vBz please give detailed reasons for all questions is there NE source for solutions 2 HCV objectives

Shamanth MM
12 Points
7 years ago
For first question . your relative velocity wrt to electron is 0 but you have relative velocity wrt to photons. So answer is A

For second question. As it is CONDUCTOR electric field inside is 0. Charge is flowing on the surface. And therefore answers are Option B(by Ampere's law) and C

For third question. Best way I know is by dimensional analysis.so you get answers b,c