Question

The value of the horizontal component of the earth's magnetic field and angle of dip are $1.8\times 10^{-5}Wb/m^2$ and $30^{\circ }$, respectively, at some place. The total intensity of earth's magnetic field at that place will be

• A. $2.08\times 10^{-5}Wb/m^2$
• B. $3.67\times 10^{-5}Wb/m^2$
• C. $3.18\times 10^{-5}Wb/m^2$
• D. $5.0\times 10^{-5}Wb/m^2$

Answer 1

Answer: (A)

Horizontal component, $B_H=B\cos \varphi$
Total intensity of earth magnetic field, $B=\frac{B_H}{\cos \varphi }$
$=\frac{1.8\times 10^{-5}}{\cos 30^{\circ }}$
$=\frac{1.8\times 10^{-5}}{\sqrt{3}/2}$
$=2.08\times 10^{-5}Wb/m^2$