${q_1},\;{q_2},\;{q_3}$ and ${q_4}$ are point charges located at points as shown in the figure and $S$ is a spherical Gaussian surface of radius $R$. Which of the following is true according to the Gauss’s law
$\oint_s {({{\vec E}_1} + {{\vec E}_2} + {{\vec E}_3}).d\vec A} = \frac{{{q_1} + {q_2} + {q_3}}}{{2{\varepsilon _0}}}$
$\oint_s {({{\vec E}_1} + {{\vec E}_2} + {{\vec E}_3}).d\vec A} = \frac{{({q_1} + {q_2} + {q_3})}}{{{\varepsilon _0}}}$
$\oint_s {({{\vec E}_1} + {{\vec E}_2} + {{\vec E}_3}).d\vec A} = \frac{{({q_1} + {q_2} + {q_3} + {q_4})}}{{{\varepsilon _0}}}$
None of the above
A hollow cylinder has a charge $q$ coulomb within it. If $\phi$ is the electric flux in units of $volt-meter$ associated with the curved surface $B,$ the flux linked with the plane surface $A$ in units of $V-m$ will be
An infinite line charge is at the axis of a cylinder of length $1 \,m$ and radius $7 \,cm$. If electric field at any point on the curved surface of cylinder is $250 \,NC ^{-1}$, then net electric flux through the cylinder is ............ $Nm ^2 C ^{-1}$
How field lines depend on area or on solid angle made by area ?
Two surfaces $S_1$ and $S_2$ are shown in figure. Flux associated with $S_1$ is ${\phi _1}$ and $S_2$ is ${\phi _2}$. Which is correct ?
A point charge $+Q$ is positioned at the centre of the base of a square pyramid as shown. The flux through one of the four identical upper faces of the pyramid is