A 545-turn circular-loop coil with a diameter of 18.8 cm is initially aligned so that its plane is perpendicular to the Earth's magnetic field. In 2.14 ms the coil is rotated 90.0 ? so that its plane is parallel to the Earth's magnetic ?eld. An average emf of 0.125 V is induced in the coil. What is the value of the Earth's magnetic field?