question_answer

A moving coil galvanometer has a coil with 175 turns and area \[1c{{m}^{2}}.\]It uses a torsion band of torsion constant \[{{10}^{-6}}\] N-m/rad. The coil is placed in a maganetic field B parallel to its plane. The coil deflects by\[1{}^\circ \]for a current of 1 mA. The value of B (in Tesla) is approximately: [JEE Main 9-4-2019 Afternoon]

A) \[{{10}^{-3}}\]

B) \[{{10}^{-1}}\]

C) \[{{10}^{-4}}\]

D) \[{{10}^{-2}}\]

Correct Answer: A

Solution :

[a]

Tesla,