In the circuit shown in the following figure, the potential difference cross $3 \mu \mathrm{~F}$ capacitor is

Sodium light $\left(\lambda=6 \times 10^{-7} \mathrm{~m}\right)$ is used to produce interference pattern. The observed fringe width is 0.12 mm . The angle between the two wave trains is

The motion of a particle is described by the equation $a=-b x$ where ' $a$ ' is the acceleration, x is the displacement from the equilibrium position and b is a constant. The periodic time will be

Acceleration of an electron in the first Bohr's orbit is proportional to $\mathrm{m}=$ mass of electron, $\mathrm{r}=$ radius of the orbit, $\mathrm{h}=$ Planck's constant)