Final answer:
The magnitude of Earth's magnetic field in Houston can be calculated using the angle below the horizontal line and the given magnitude. The answer is 2.38×10⁻⁵ T.
Step-by-step explanation:
The magnitude of Earth's magnetic field in Houston can be determined using the given information. The magnitude of the magnetic field is 5.2×10⁻⁵ T and it points 57° below a horizontal line pointing north. We can break down the magnetic field into horizontal and vertical components. The horizontal component is given by Bx = B*cosθ, where B is the magnitude of the magnetic field and θ is the angle below the horizontal line. Substituting the values, we get Bx = 5.2×10⁻⁵ T * cos(57°). Solving this equation gives us Bx = 2.38×10⁻⁵ T.