# At a certain place the angle of dip 300 and the horizontal component of earth's magnetic field is 0.50 oerested. The earths's total magnetic field (in oerested) is (A) √3 (B) 1 (C) (1/√3) (D) 1/2

We know that,

$B&space;=&space;\frac{H}{cos&space;\theta}$

On substituting

$B&space;=&space;\frac{0.50}{cos&space;30^{0}}$

$B&space;=&space;\frac{0.50\times&space;2}{\sqrt{3}}$

We get,

$B&space;=&space;\frac{1}{\sqrt{3}}$

Therefore, the earth’s total magnetic field is (1/√3)

So, the correct option is (C)