Question

At a certain place, the angle of dip ${30}^o$ and the horizontal component of earth's magnetic field is $0.50$ oerested.The earth's total magnetic field (in oerested) is

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

Answer 1

Answer: (C)

$\frac{1}{\sqrt{3}}$

$B=\frac{H}{\cos \theta }$
$=\frac{0.50}{\cos {30}^o}$
$=\frac{0.50\times 2}{\sqrt{3}}$
$=1/\sqrt{3}$