Two uniform magnetic fields B and H are perpendicular to each other. At a place when a magnetic needle is placed in the field, it rest making angle of 60° and 30° with B and H respectively. The value of B: H is:

Question

Two uniform magnetic fields B and H are perpendicular to each other. At a place when a magnetic needle is placed in the field, it rest making angle of 60° and 30° with B and H respectively. The value of B: H is: (A) 1: 2 (B) 2: 1 (C) √3: 1 (D) 1: √3

Tardigrade Admin · Accepted Answer

B=B0 cos 60° H=B0 cos 30° (B/H)=( cos 60°/ cos 30°) =(1 / 2/√3 / 2)=(1/√3)

Q. Two uniform magnetic fields $B$ and $H$ are perpendicular to each other. At a place when a magnetic needle is placed in the field, it rest making angle of $6 0^{\circ}$ and $3 0^{\circ}$ with $B$ and $H$ respectively. The value of $B : H$ is:

$1 : 2$

$2 : 1$

$3 : 1$

$1 : 3$

$B = B_{0} cos 6 0^{\circ}$
$H = B_{0} cos 3 0^{\circ}$
$\frac{B}{H} = \frac{c o s 6 0 ^{\circ}}{c o s 3 0 ^{\circ}}$
$= \frac{1/2}{3 /2} = \frac{1}{3}$

Q. Two uniform magnetic fields B and H are perpendicular to each other. At a place when a magnetic needle is placed in the field, it rest making angle of 60∘ and 30∘ with B and H respectively. The value of B:H is:

1:2

2:1

3​:1

1:3​