Q. A dip needle lies initially in the magnetic meridian when it shows an angle of dip $\theta$ at a place. The dip circle is rotated through an angle $x$ in the horizontal plane and then it shows an angle of dip $\theta$’. Then $\frac{\tan\theta^{'}}{\tan\theta}$ is
A) $\frac{1}{\cos x}$
B) $\frac{1}{\sin x}$
C) $\frac{1}{\tan x}$
D) $\cos x$
Explanation
(a) In first case $\tan\theta = \frac{B_{V}}{B_{H}}\ \ $ …(i)
Second case $\tan\theta = \frac{B_{V}}{B_{H}\cos x}$ …(ii)
From equation (i) and (ii), $\frac{\tan\theta^{'}}{\tan\theta} = \frac{1}{\cos x}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.