Two straight parallel conductors are kept horizontally one above the other. If the upper wire suspends in air without any support, then the direction of flow of current in the wires should be

Options

A. in same direction
B. in opposite direction
C. in the same or opposite directions
D. the wires should be perpendicular

Answer

To solve the problem, we need to analyze the situation of two parallel conductors with respect to the flow of current and the forces acting on them due to their magnetic fields.

### Step-by-Step Solution:

1. **Understanding the Setup**:
We have two straight parallel conductors. One is positioned above the other horizontally. The upper wire is suspended in air without any support, indicating that there are forces acting on it.

**Hint**: Visualize the arrangement of the two wires and the forces that could be acting on the upper wire.

2. **Direction of Current and Magnetic Field**:
When current flows through a conductor, it generates a magnetic field around it. The direction of the magnetic field can be determined using the right-hand rule.

**Hint**: Remember that the right-hand rule helps in determining the direction of the magnetic field created by a current-carrying conductor.

3. **Force Between the Conductors**:
According to Ampère's force law, two parallel conductors carrying current will exert forces on each other. If the currents in both conductors flow in the same direction, they will attract each other. Conversely, if the currents flow in opposite directions, they will repel each other.

**Hint**: Recall the relationship between the direction of current and the resulting magnetic forces between two conductors.

4. **Analyzing the Upper Wire**:
Since the upper wire is suspended in air without any support, there must be a force acting on it that counteracts gravity. For the upper wire to be suspended, the magnetic force exerted by the lower wire must be acting upwards.

**Hint**: Consider how the direction of the magnetic force depends on the direction of the current in the lower wire.

5. **Determining the Current Direction**:
If the upper wire is suspended due to the magnetic force from the lower wire, the currents in both wires must be in opposite directions. This is because:
- If the current in the lower wire flows in one direction, it creates a magnetic field that exerts an upward force on the upper wire.
- If both currents flowed in the same direction, the upper wire would experience a downward force due to attraction, which would not allow it to suspend.

**Hint**: Think about the implications of the forces acting on the upper wire based on the direction of the currents.

6. **Conclusion**:
Therefore, for the upper wire to remain suspended in air without any support, the direction of the flow of current in the wires must be opposite to each other.

**Final Answer**: The direction of flow of current in the wires should be opposite.