Water from a tap of cross-sectional area $$1 \mathrm{~cm}^2$$, falls vertically downwards at $$2 \mathrm{~m} / \mathrm{s}$$. The cross sectional area of the stream, $$20 \mathrm{~cm}$$ below the tap is (assume that pressure is constant throughout and the flow is streamlined; $$\left(\mathrm{g}=10 \mathrm{~ms}^{-2}\right)$$
In the figure, first the capacitors are fully charged by closing the key $$\mathrm{K}$$. Then after opening the Key a dielectric material with dielectric constant 2 is filled in the space between the plates of both the capacitor. At this state the ratio of the Charge on the capacitor $$C_1$$ to that of $$C_2$$ is:
The energy gap between valance band and the conduction band for a given material is $$6 \mathrm{~eV}$$, then the material is :
PQRS is square of side $$1 \mathrm{~m}$$. A charge of $$100 \mu \mathrm{C}$$ is placed at the centre of the square. Then the work done to take $$3 \mu \mathrm{C}$$ charge from the corner $$\mathrm{P}$$ to the corner $$\mathrm{R}$$.