Question

At a place the value of $B_H$ and $B_V$ are $0.4\times {10}^{-4}$and $0.3\times {10}^{-4}$respectively. The resultant earths magnetic field is :

• A. $0.5\times {10}^{-4}T$
• B. ${10}^{-4}T$
• C. $2\times {10}^{-4}T$
• D. $5\times {10}^{-4}T$

Answer 1

The correct option is A $0.5\times {10}^{-4}T$

$I=\sqrt{B{{}_H}^2+B{{}_V}^2}$
$=\sqrt{{(0.4\times {10}^{-4})}^2+{(0.3\times {10}^{-4})}^2}$
$=0.5\times {10}^{-4}$ T