Question

Difficulty: MediumMagnetism and Earth's Magnetic Field

A magnetometer stationed at a field site records the horizontal component of the Earth's magnetic field as 36 μT36\ \mu\text{T} and the total magnetic field intensity as 45 μT45\ \mu\text{T}. What is the magnitude of the vertical component of the Earth's magnetic field, in μT\mu\text{T}?

Answer: 27 μT

Answer

The magnitude of the vertical component of the Earth's magnetic field is 27 μT27\ \mu\text{T}.
The total magnetic field strength BB is the hypotenuse of a right-angled triangle formed by the horizontal component BhB_h and vertical component BvB_v. By applying the Pythagorean relation B2=Bh2+Bv2B^2 = B_h^2 + B_v^2, substituting B=45 μTB = 45\ \mu\text{T} and Bh=36 μTB_h = 36\ \mu\text{T} yields Bv=452362=729=27 μTB_v = \sqrt{45^2 - 36^2} = \sqrt{729} = 27\ \mu\text{T}.

Step-by-Step Solution

1
Relate total magnetic intensity to its orthogonal components
B2=Bh2+Bv2B^2 = B_h^2 + B_v^2
The total magnetic field vector of the Earth is the vector sum of mutually perpendicular horizontal and vertical components.
2
Isolate the vertical component variable
Bv=B2Bh2B_v = \sqrt{B^2 - B_h^2}
Applying the Pythagorean theorem allows direct calculation of the missing perpendicular side.
3
Substitute given values and compute numerical result
Bv=452362=20251296=729=27 μTB_v = \sqrt{45^2 - 36^2} = \sqrt{2025 - 1296} = \sqrt{729} = 27\ \mu\text{T}
Evaluates the exact magnitude of the vertical component.

Key Concept

Orthogonal resolution of Earth's magnetic field components
Estimated Time:1m 15s
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