A potential barrier of 0.4 V exists across a p-n junction. An electron enters the junction from the n-side with a speed of 6.0 $$\times$$ 10⁵ ms^$$-$$1. The speed with which electron enters the p side will be $${x \over 3} \times {10^5}$$ ms^$$-$$1 the value of x is _____________.

(Given mass of electron = 9 $$\times$$ 10^$$-$$31 kg, charge on electron = 1.6 $$\times$$ 10^$$-$$19 C.)

The displacement current of 4.425 $$\mu$$A is developed in the space between the plates of parallel plate capacitor when voltage is changing at a rate of 10⁶ Vs^$$-$$1. The area of each plate of the capacitor is 40 cm². The distance between each plate of the capacitor is x $$\times$$ 10^$$-$$3 m. The value of x is __________.

(Permittivity of free space, E₀ = 8.85 $$\times$$ 10^$$-$$12 C² N^$$-$$1 m^$$-$$2).

The moment of inertia of a uniform thin rod about a perpendicular axis passing through one end is I₁. The same rod is bent into a ring and its moment of inertia about a diameter is I₂. If $${{{I_1}} \over {{I_2}}}$$ is $${{x{\pi ^2}} \over 3}$$, then the value of x will be ____________.

In a double slit experiment with monochromatic light, fringes are obtained on a screen placed at some distance from the plane of slits. If the screen is moved by 5 $$\times$$ 10^$$-$$2 m towards the slits, the change in fringe width is 3 $$\times$$ 10^$$-$$3 cm. If the distance between the slits is 1 mm, then the wavelength of the light will be ____________ nm.