Question

A wire carries a current with a magnitude I = 0.25 A. What is the magnitude of the magnetic field induced by the current at a distance of 0.13 m from the wire?

A. 7.7×10⁻⁷ T

B. 3.8×10⁻⁷ T

C. 2.6×10⁶ T

D. 1.9×10⁻⁷ T

Answer 1

From Biot-savart law

Magnetic field due to a current carrying wire at distance of a is equal to  ° I / 2a

Where ° = permittivity of free space =4×10^(-7)

I = current carrying =0.25 A

a=0.13 m

Magnetic field = 4××10^(-7)×0.25/(2××0.13)

= 3.8×10^(-7) T

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