An $\alpha \text{-particle }$travels in a circular path of radius 0.45 m in a magnetic field B = 1.2 Wb/m² with a speed of $2.6\times {10}^7 \text{m}/\text{s}$. The period of revolution of the $\alpha \text{-particle }$

• A

  $1.1\times {10}^{-5} \text{s}$

• B

  $1.1\times {10}^{-6} \text{s}$

• C

  $1.1\times {10}^{-7} \text{s}$

• D

  $1.1\times {10}^{-8} \text{s}$