question_answer

A magnetic dipole is acted upon by two magnetic fields which are inclined to each other a tan angle of \[75{}^\circ \]. One of the fields has magnitude of 15mT. The dipole attains stable equilibrium at an angle \[30{}^\circ \] with this field. The magnitude of the other field (in mT) is close to :   JEE Main Online Paper (Held On 09 April 2016)

A) 11          

B) 1060

C) 36                                          

D) 1

Correct Answer: A

Solution :

Sol. \[{{B}_{1}}\sin {{30}^{o}}=B2\sin {{45}^{o}}\] \[{{B}_{2}}\frac{{{B}_{1}}}{\sqrt{2}}=10.60mT\approx 11mT\]