Question

Suppose a room has a magnetic field, directed downwards. Then in which way should the straight conductor be placed in order to experience maximum magnetic force?

• A. Place the wire vertically
• B. Place the wire along the line of the body diagonal (line joining one corner to opposite corner through the room space is called body diagonal)
• C. Place the wire horizontally
• D. Place the wire in the next room

Answer 1

The correct option is C

Place the wire horizontally

The magnetic force on a current-carrying wire depends on the magnitude of current and the strength of magnetic field. The force is maximum when the direction of current and the field are perpendicular to each other. Since here, the direction of magnetic field is acting downwards, the current carrying wire must be kept horizontal for it to be perpendicular to the magnetic field. Also, a point to be kept in mind is that this force is minimum (i.e. zero), if the current carrying wire and the field are along the same direction.