The magnetic induction at a pont point P which is at the distance of 4 cm from a long current carrying wire is 10-3 T. The field of induction at a distance 12 cm from the current will be

Question

The magnetic induction at a pont point P which is at the distance of 4 cm from a long current carrying wire is 10-3 T. The field of induction at a distance 12 cm from the current will be (A) 3.33 × 10-4 T  (B) 1.11 × 10-4 T  (C) 33 × 10-3 T  (D)  9 × 10-3 T

Tardigrade Admin · Accepted Answer

B propto 1 / r. By AmpÃ¨re's law. As the distance is increased to three times, the magnetic induction reduces to one third. Hence B=(1/3) × 10-3 tesla =3.33 × 10-4 tesla

Q. The magnetic induction at a pont point $P$ which is at the distance of $4 c m$ from a long current carrying wire is $1 0^{- 3} T$ . The field of induction at a distance $12 c m$ from the current will be

$3.33 \times 10^{- 4} T$

$1.11 \times 10^{- 4} T$

$33 \times 10^{- 3} T$

$9 \times 10^{- 3} T$

$B \propto 1/ r$ . By Ampère's law.
As the distance is increased to three times, the magnetic induction reduces to one third.
Hence $B = \frac{1}{3} \times 1 0^{- 3}$ tesla $= 3.33 \times 1 0^{- 4}$ tesla

Q. The magnetic induction at a pont point P which is at the distance of 4cm from a long current carrying wire is 10−3T. The field of induction at a distance 12cm from the current will be

3.33×10−4T

1.11×10−4T

33×10−3T

9×10−3T