A circular calibration coil on a spacecraft is initially held in a vertical orientation. A constant direct current passes through the coil, producing a magnetic field. At the center of the coil, QQQ, the magnetic flux density is entirely horizontal, with a magnitude of BHB_{\text{H}}BH.
The coil is then rotated about a horizontal axis through QQQ by an angle of 34∘34^\circ34∘, so that the plane of the coil makes an angle of 34∘34^\circ34∘ with the vertical, as shown in the diagram below. The current in the coil remains unchanged.
Determine the percentage change in the horizontal component of the magnetic flux density, BHB_{\text{H}}BH, at point QQQ caused by this rotation. Show your working.