How much energy is stored in a room 3.0 m by 4.0 m by 2.4 m due to the earth's magnetic field with a strength of 5.0 × 10^-5 T? (μ₀ = 4π × 10^-7 T • m/A) A) 570 mJ. B) 29 mJ. C) 10 mJ. D) 100 mJ.

Question

Quizplus · Accepted Answer

The energy stored in a magnetic field can be calculated using the equation:

E = (1/2) μ V B^2

Where E is energy, μ is the permeability of the material (in this case, vacuum), V is the volume, and B is the magnetic field strength.

Substituting the given values, we get:

E = (1/2) (4π × 10^-7 T•m/A) (3.0 m × 4.0 m × 2.4 m) (5.0 × 10^-5 T)^2
E ≈ 29 mJ

Therefore, the correct answer is B.

How Much Energy Is Stored in a Room 3