A short magnetic needle is pivoted in a uniform magnetic field of induction $1 \mathrm{~T}$. Now, simultaneously another magnetic field of induction $\sqrt{3} \mathrm{~T}$ is applied at right angles to the first field; the needle deflects through an angle $\theta$ whose value is

• A

  $30^{\circ}$
• B

  $45^{\circ}$
• C

  $90^{\circ}$
• Correct answer
  D

  $60^{\circ}$

Solution

In balance condition $B_2=B_1 \tan \theta$ or $\quad \tan \theta=\frac{\sqrt{3}}{1}=\sqrt{3}$ $\theta=60^{\circ}$

Hence, the correct answer is option: 'D'.