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A solenoid is 1.1 m long and has 490 turns per meter. What is the cross-sectional area of this solenoid if it stores 0.37 J of energy when it carries a current of 11 A ? Express your answer using two significant figures.

User Oxyum
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1 Answer

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To find the cross-sectional area of the solenoid, we can use the formula for the energy stored in an inductor:

E = (1/2) * μ₀ * N² * A * I² / L

Where:

E is the energy stored in the solenoid,

μ₀ is the permeability of free space (approximately 4π × 10^(-7) T·m/A),

N is the number of turns per unit length,

A is the cross-sectional area of the solenoid,

I is the current flowing through the solenoid,

L is the length of the solenoid.

In this case, we are given:

E = 0.37 J,

N = 490 turns/m,

I = 11 A,

L = 1.1 m.

Rearranging the formula, we can solve for A:

A = (2 * E * L) / (μ₀ * N² * I²)

Substituting the given values:

A = (2 * 0.37 J * 1.1 m) / (4π × 10^(-7) T·m/A * (490 turns/m)² * (11 A)²)

Calculating this expression gives us:

A ≈ 0.00443 m²

Therefore, the cross-sectional area of the solenoid is approximately 0.00443 square meters.

User Sergio Andreotti
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