Question

Due to 10 ampere of current flowing in a circular coil of 10 cm radius, the magnetic field produced at its centre is . The number of turns in the coil will be

• A. 5000
• B. 100
• C. 50
• D. 25

Answer 1

Answer: (C)

50

Answer 2

$B = \frac { \mu _ { 0 } } { 4 \pi } \cdot \frac { 2 \pi N i } { r }$

⇒ $3.14 \times 10 ^ { - 3 } = \frac { 10 ^ { - 7 } \times 2 \times 3.14 \times N \times 10 } { \left( 10 \times 10 ^ { - 2 } \right) }$ ⇒ $N = 50$