Q. The magnetic needle of a tangent galvanometer is deflected at an angle $30{^\circ}$ due to a magnet. The horizontal component of earth’s magnetic field $0.34 \times 10^{- 4}$ T is along the plane of the coil. The magnetic intensity is
A) $1.96 \times 10^{- 4}$ T
B) 1.96$\times 10^{4}$ T
C) 1.96$\times 10^{- 5}$ T
D) 1.96$\times 10^{5}$ T
Explanation
(c) In a tangent galvanometer, applying tangent law $B = H\tan\theta$
$B = 0.34 \times 10^{- 4}\ tan30{^\circ} = 0.34 \times 10^{- 4} \times \frac{1}{\sqrt{3}}$
$B = 1.96 \times 10^{- 5}$ T.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.