1But in H.C.Verma ,the answer is given as μoi2πr. someone tell the reason pls. HCV page no. 249 Q.no. 12
Q. 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 troley moving in a direction opposite to the current with a speed inAe and separated from the wire by a distance r. What is the magnetic field seen by the observer????
-
UP 0 DOWN 0 0 11
11 Answers
1
66The current in the new frame is the same as the old one, since any change in the current due to the change in drift velocity is compensated by an opposite current which arises due to the motion of the positive ions in the new frame.
1actually i think everyones igonored the fact that the movement of elctrons is in the opp direction of that of the current so in relaity the observer doesnt notice an electric field it notices a magnetic field due to the current i
1What is the reason that a charged particle moving parallel to the current carrying wire, with a velocity 'v' in the same direction as current is deflected towards it even when seen from a frame which moves at same speed of that of the charged partical?
1The reason is that in a moving frame, the length and volume of the region containing conduction electrons appear shorter due to relativistic contraction of the distances. Hence, the charge density of the wire changes with the frame of reference. For a moving frame, both -ve and +ve charge appears to move with different velocities. This motion results in different -ve and +ve charge densities and length contraction.
We can say that magnetic field manifest ates itself as electric field .
For mathematical completeness, refer to JD Jackson or The Feynman lectures
