A particle is performing uniform circular motion along the circumference of the circle of diameter 1 m with frequency 4 Hz . The acceleration of the particle in $\mathrm{m} / \mathrm{s}^2$ is

A uniformly charged conducting sphere of diameter 14 cm has surface charge density of $40 \mu \mathrm{Cm}^{-2}$. The total electric flux leaving the surface of the sphere is nearly (Permittivity of free space $=8.85 \times 10^{-12}$ SI unit)

The acceleration of a moving body can be found from

Two identical current carrying coils with same centre are placed with their planes perpendicular to each other. If current $\mathrm{I}=\sqrt{2} \mathrm{~A}$ and radius of the coil is $R=1 \mathrm{~m}$, then magnetic field at centre is equal to ( $\mu_0=$ permeability of free space)