Electric Charge...

In the figure distance of the point from $$A$$, where the electric field is zero is:-

A solid metallic sphere has a charge +3Q concentric with this sphere is a conducting spherical shell having charge O. The radius of the sphere is a and that of the spherical shell is b(>a). What is the  electric field at a distance r(a < r < b) from the centre? 

A capacitor is a perfect insulator for:

A point charge $$50 \: \mu C$$ is located in the $$XY $$ plane at the point of position vector $$ r_1 = 2i + 3j $$ . What is the electric field at the point of position vector $$r_2 = 8i-5j$$.

In order to balance the weight of an electron in an electric field E the magnitude and the direction of the electric field will be ( g = 10 $$m/s^2$$)

A charge  q is divided into two parts $${ q }_{ 1 }$$ and ($${q} - { q }_{ 1 }$$) What is the ratio q /$${ q }_{ 1 }$$ so that the force between the two parts when placed a given distance apart is maximum:

There are two point charges $$q_1$$ and $$q_2$$ lying on a circle of unit radius. Electric field intensity at the center of circle due to these charges is $$\vec { E }$$. Find the position vector of the center with respect to $$q_2$$ is $$\vec { r } _ { 1 }$$

What is the value of electric flux in SI unit in the Y-Z plane of area $$2{m^2}$$ , if intensity of electric field is $$\overrightarrow {\text{E}} {\text{ = }}\left( {{\text{5}}\widehat {\text{i}}{\text{ + 2}}\widehat {\text{j}}} \right){\text{N/C}}$$

A cone of base radius R and height $$h$$ is located in a uniform electric field $${\vec E}$$ parallel to its base. The electric flux entering the cone is 

Three charges $${q_1} = 1 \times {10^{ - 8}},{q_2} = 2 \times {10^{ - 6}},{q_3} =  - 3 \times {10^{ - 6}}$$ have been placed, as shown in figure, in four surfaces $${S_1},{S_2},{S_3}$$ and $${S_4}$$ electrical flux emitted from the surface $${S_2}$$ in $$N - {m^2}/C$$ wil be