Question

A straight wire carrying a current of 13 A bent into a semi-Circular arc of radius 2 cm as shown in figure. The magnetic field is 1.5 × 10-4 T at the centre of arc, then the magnetic field due to straight segment is

• A. 1.5 × 10-4 T
• B. 2.5 × 10-4 T
• C. Zero
• D. 3 × 10-4 T

Answer 1

Answer: (C)

Zero

Answer 2

Since dl and r for each element of the straight segments are parallel therefore

$\overrightarrow { \mathrm { dl } } \times \overrightarrow { \mathrm { r } } = 0$

Hence B is also zero.