A diamagnetic liquid is filled in a U-tube. One arm of a U-tube is placed in an external magnetic field with the meniscus in line with the field. The level of the liquid in that arm will

Diamagnetic substances are repelled by magnetic fields and tend to move from regions of stronger magnetic field to regions of weaker magnetic field.

When one arm of the U-tube containing a diamagnetic liquid is placed in an external magnetic field, the liquid experiences a force pushing it away from the stronger field region.

As a result, the level of the liquid in the arm placed in the magnetic field will fall.

Answer: fall.