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