Question

The angle of dip at a place is $ {{37}^{o}} $ and the vertical component of the earths magnetic field is $ 6\times {{10}^{-5}}T. $ The earths magnetic field at this place is $ (tan\text{ }{{37}^{o}}=3/4) $

• A. $ 7\times {{10}^{-5}}T $
• B. $ 6\times {{10}^{-5}}T $
• C. $ 5\times {{10}^{-5}}T $
• D. $10\times {{10}^{-4}}T $
• E. $ 4\times {{10}^{-5}}\,T $

Answer 1

Answer: (D)

Given: $ \tan {{37}^{o}}=\frac{3}{4} $
The vertical component of the earths magnetic field
$ {{B}_{V}}=6\times {{10}^{-5}}T $
$ \sin {{37}^{o}}=\frac{3}{5} $
For vertical component $ {{B}_{V}}=B\sin \theta $
Or $ B=\frac{{{B}_{V}}}{\sin \theta } $
Or $ B=\frac{6\times {{10}^{-5}}}{3}\times 5 $
Or $ B=10\times {{10}^{-5}} $
Or $ B={{10}^{-4}}T $