Question

The angle of dip at a certain place is 30^o. If the horizontal component of the earth’s magnetic field is H, the intensity of the total magnetic field is

• A. $\frac { H } { 2 }$
• B. $\frac { 2 H } { \sqrt { 3 } }$
• C. $H \sqrt { 2 }$
• D. $H \sqrt { 3 }$

Answer 1

Answer: (B)

$\frac { 2 H } { \sqrt { 3 } }$

Answer 2

$B _ { H } = B \cos \phi \Rightarrow B = \frac { B _ { H } } { \cos \phi } \Rightarrow B = \frac { B _ { H } } { \cos 30 ^ { \circ } } = \frac { 2 B _ { H } } { \sqrt { 3 } }$