Question

At two different places the angles of dip are respectively $30^{\circ}$ and $45^{\circ}$. At these two places the ratio of horizontal component of earth?s magnetic field is

• A. $\sqrt{3}:\sqrt{2}$
• B. $1:\sqrt{2}$
• C. $1:2$
• D. $1:\sqrt{3}$

Answer 1

Answer: (A)

$\sqrt{3}:\sqrt{2}$

Answer 2

The horizontal component of earth's magnetic field is given by, $H=R \cos \delta$
where, $\delta$ is the angle of dip so $H_{1}=R \cos 30^{\circ}$
and $H_{2}=R \cos 45^{\circ}$
$\therefore \frac{H_{1}}{H_{2}}=\frac{R \cos 30^{\circ}}{R \cos 45^{\circ}}=\frac{\sqrt{3} / 2}{1 / \sqrt{2}}=\frac{\sqrt{3}}{\sqrt{2}}$