Question

At a certain place the angle of dip is ${30}^{\circ }$ and the horizontal component of earth's magnetic field is $0.5G$ . The earth's total magnetic field (in $G$ ), at that certain place, is :

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

Answer 1

The correct option is B $\frac{1}{\sqrt{3}}$

Horizontal component of earth's magnetic field $\left(B_H\right)=B\cos {30}^{\circ }$

$\Rightarrow B\times \frac{\sqrt{3}}{2}=0.5\times G$

$B=\frac{1}{\sqrt{3}}\times G$

$\therefore$ option $\left(a\right)$ is correct choice.