A magnetised steel wire 31.4 cm long has pole strength of 0.2 Am . It is then bent in the form of a semicircle. What is the magnetic moment of the semicircle?

Question

A magnetised steel wire 31.4 cm long has pole strength of 0.2 Am . It is then bent in the form of a semicircle. What is the magnetic moment of the semicircle? (A) 0.04 Am 2 (B) 0.05 Am 2 (C) 0.06 Am 2 (D) 0.07 Am 2

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/3712b7d7fb157f9561e65340fa0bed47-.png" /> When the wire is bent in the form of a semicircle of radius r, then L =π r =3.14 r r=(L/3.14)=(31.4/3.14)=10 cm Distance between the two ends of wire 2 r=20 cm =0.2 m M=m × 2 r=0.2 × 0.2 M =0.04 Am 2

Q. A magnetised steel wire $31.4 c m$ long has pole strength of $0.2 A m .$ It is then bent in the form of a semicircle. What is the magnetic moment of the semicircle?

$0.04 A m^{2}$

$0.05 A m^{2}$

$0.06 A m^{2}$

$0.07 A m^{2}$

When the wire is bent in the form of a semicircle of radius $r$ , then
$L = π r = 3.14 r$
$r = \frac{L}{3.14} = \frac{31.4}{3.14} = 10 c m$
Distance between the two ends of wire
$2 r = 20 c m = 0.2 m$
$M = m \times 2 r = 0.2 \times 0.2$
$M = 0.04 A m^{2}$

Q. A magnetised steel wire 31.4cm long has pole strength of 0.2Am. It is then bent in the form of a semicircle. What is the magnetic moment of the semicircle?

0.04Am2

0.05Am2

0.06Am2

0.07Am2