Magnetic Effects of Curre question bank (Physics)

The magnitude of the magnetic induction (B) at a point on the axis at a large distance 'r' from the centre of a circular coil of 'n' turns and area 'A' carrying current ' i ' is given by $x \times 10^{-7}$ SI unit. The value of x is $(\mu_0 = 4\pi \times 10^{-7}$ SI unit$)$

The ratio of cyclotron frequency $f$ to the radius of the path of a charged particle $R$ is $\dfrac{q^2 B^2}{2\pi m^2}x$. Then the value of $x$ is ( $v$ is velocity of charged particle)