question_answer

A long straight wire carries a current of 35 A. What is the magnitude of the field B at a point 30 cm from the wire?

Answer:

Here, Z = 35 A and R = 30 cm = 0.3 m \[\therefore \] \[B=\frac{{{\mu }_{0}}I}{2\pi R}=\frac{4\pi \times {{10}^{-7}}\times 35}{2\pi \times 0.3}=2.33\times {{10}^{-5}}T\]