At a certain location in Africa, compass points `12^@` west of geographic north, figure. The north tip of magnetic needle of a dip circle placed in the plane of magnetic meridian points `60^@` above the horizontal. The horizontal component of earth's field is measured to be `0.16 gauss`. Specify the direction and magnitude of the earth's field at the location.

Options

A. 0.32G
B. 0.42G
C. 4.2G
D. 3.2G

Answer

A

Explanation

`"Here", H_(E)=0.16G=0.16xx10^(-4)T`
dipm angle `(delta)=60^(@)`
Then magnitude of earth's field
`B_(E)=(H_(E))/(cos delta)=(0.16xx10^(-4))/(cos 60^(@))T Rightarrow B_(E)=(0.16xx10^(-4))/(1//2)`
`=0.32xx10^(-4)T =0.32G`