Question

A conductor ABCDE, shaped as shown, carries current I. It is placed in the x-y plane with the ends A and E on the x-axis. A uniform magnetic field of magnitude B exists in the region. The force acting on it will be

• A. zero, if B is in the x-direction
• B. $\lambda BI$ in the z-direction, if B is in the y-direction
• C. $\lambda BI$ in the negative y-direction, if B is in the z-direction
• D. $\lambda aBI$, if B is in the x-direction

Answer 1

Answer: (A), (B), (C)

zero, if B is in the x-direction
$\lambda BI$ in the z-direction, if B is in the y-direction
$\lambda BI$ in the negative y-direction, if B is in the z-direction

To find the Ampere's force on a conductor of any shape, replace the conductor by an imaginary straight conductor joining the two ends of the given conductor. So, if B is in x-direction, then the imaginary straight conductor will be along the field and the force acting on it will zero. If B is in y direction, then the force will be BI acting along the z direction. Similarly, If B is in the z direction, then the force will be BI, acting along the negative y direction.