The strength of the magnetic field at a point r near a long straight current-carrying wire is B. The field at a distance \(\frac{r}{2}\) will be _____.
A. \(\frac{\mathrm{B}}{2}\)
B. \(\frac{\mathrm{B}}{4}\)
C. 2B
D. 4B
Answer:C
The strength of the magnetic field at a point r near a long straight current-carrying wire is B. The field at a distance \(\frac{r}{2}\) will be _____.
A. \(\frac{\mathrm{B}}{2}\) B. \(\frac{\mathrm{B}}{4}\) C. 2B D. 4B