When a liquid rises in a capillary tube, it does so due to capillary action, which is caused by the adhesive forces between the liquid molecules and the walls of the tube. In this case, the angle at which the tube is inclined to is 45°.

When a capillary tube is inclined, the force of gravity acting on the liquid column can be resolved into two components: one parallel to the tube and one perpendicular to the tube.

In this scenario, the perpendicular component of the gravitational force will counterbalance the adhesive forces between the liquid and the tube walls, resulting in a decrease in the length of the liquid column.

Therefore, when the capillary tube is inclined to an angle of 45°, the length of the liquid column will decrease.

It is important to note that the decrease in length will depend on the nature of the liquid, the diameter of the tube, and other factors.