KCET2026PhysicsMagnetic Effects of Current
Biot-Savart law indicates that an electron moving with a velocity V produces a magnetic field B around it such that
Options
- AB is parallel to V
- BB is perpendicular to V
- CB is anti-parallel to V
- DB is inclined to V by 45^
Correct answer
B. B is perpendicular to V
Step-by-step solution
According to the Biot-Savart law, the magnetic field B produced by a charge q moving with velocity V at a position vector r is given by B = ₀ 4 q( V r ) r^3 The direction of the magnetic field B is determined by the cross product V r . By the properties of the cross product, the resulting vector B is always perpendicular to both the velocity vector V and the position vector r . Therefore, B is perpendicular to V . Answer: B is perpendicular to V