A body having specific charge 8 $$\mu$$C/g is resting on a frictionless plane at a distance 10 cm from the wall (as shown in the figure). It starts moving towards the wall when a uniform electric field of 100 V/m is applied horizontally towards the wall. If the collision of the body with the wall is perfectly elastic, then the time period of the motion will be _______________ s.

An infinite number of point charges, each carrying 1 $$\mu$$C charge, are placed along the y-axis at y = 1 m, 2 m, 4 m, 8 m ...............

The total force on a 1C point charge, placed at the origin, is x $$\times$$ 10³ N.

The value of x, to the nearest integer, is __________. [Take $${1 \over {4\pi {\varepsilon _0}}} = 9 \times {10^9}$$ Nm²/C²]

The electric field intensity produced by the radiation coming from a 100 W bulb at a distance of 3 m is E. The electric field intensity produced by the radiation coming from 60W at the same distance is $$\sqrt {{x \over 5}} $$E. Where the value of x = ____________.

The electric field in a region is given by $$\overrightarrow E = {2 \over 5}{E_0}\widehat i + {3 \over 5}{E_0}\widehat j$$ with $${E_0} = 4.0 \times {10^3}{N \over C}$$. The flux of this field through a rectangular surface area 0.4 m² parallel to the Y-Z plane is __________ Nm²C^$$-$$1.