Question

A dip needle arranged to move freely in the magnetic meridian dips by an angle $\theta$. If the vertical plane in which the needle moves is rotated through an angle $\alpha$ to the magnetic meridian, then the needle will dip by an angle

• A. $\theta$
• B. $\alpha$
• C. more than $\theta$
• D. less than $\theta$

Answer 1

Answer: (C)

In this question, $\cos \alpha<1$
i.e., $\frac{1}{\cos \alpha}>1$
or, $\frac{\tan \theta '}{\tan \theta}>1$
or, $\tan \theta ' > \tan \theta$
or, $\theta ' >\theta$
ie, angle of apparent dip is more than angle of actual dip $\theta$.