Question

Suppose a straight 1.25 mm -diameter copper wire could just "float" horizontally in air because of the force due to the Earth's magnetic field B⃗ , which is horizontal, perpendicular to the wire, and of magnitude 6.4×10⁻⁵ T .

Part A

What current would the wire carry?

Express your answer using two significant figures.

Part B

Does the answer seem feasible?

Does the answer seem feasible?

	yes
	no

Answer 1

as per equilibrium of forces

mg = B i L

density * volume * g = B i L

8.96* 10^3* 3.14* (1.25* 10^-3 / 2)^2* L * 9.8 = 6.4* 10^-5* i L

i = 171.72 A

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b)

yes, this current is feasible

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