Let there are "n" number of charges (e) per unit volume and an electric current "I" is passing through it.
Volume of conductor = V = area x length = a x L Number of electrons = N = n . Volume Charge on each electron = e Total charge = q= Ne We know that the force experienced by a charge in a uniform magnetic field is | |||
| F = Q (V x B ) | ||
| Putting the value of "q" F = Ne (vBSinq) F = nV. e(vBSinq) F = ne . aL (vBSinq) F = naLe (v B Sinq) | ||
| Now consider the length of conductor (L) as a vector quantity in the direction of velocity vector. | ||
| F = nave(Lv B Sinq) F = nave(LB Sinq) | ||
| Since S = vt v = s/t v = L/t | ||
| Putting the value of v | ||
| F = na(L/t)e (L B Sinq) F = naLe/t (L B Sinq) | ||
| Since naLe = q Therefore, | ||
| F = q/t (L B Sinq) | ||
Also q/t = I | |||
| F = I (L B Sinq) | ||
| F = ILB Sinq | ||
| The expression clearly indicates that the force acting on the wire when placed in a uniform magnetic field is perpendicular to the plane formed by the L and B. i.e. F is perpendicular to L and also perpendicular to B. | ||