The figure shows two situations in which a Gaussian cube sits in an electric field. The arrows and values indicate the directions and magnitudes (in $N-m^2/C$) of the electric fields. What is the net charge (in the two situations) inside the cube?

Electric charge is uniformly distributed along a long straight wire of radius $1\, mm$. The charge per $cm$ length of the wire is $Q$ $coulomb$. Another cylindrical surface of radius $50$ $cm$ and length $1\,m$ symmetrically encloses the wire as shown in the figure. The total electric flux passing through the cylindrical surface is

If atmospheric electric field is approximately $150 \,volt / m$ and radius of the earth is $6400 \,km$, then the total charge on the earth's surface is .......... coulomb

Three charges $q_1 = 1\,\mu c, q_2 = 2\,\mu c$ and $q_3 = -3\,\mu c$ and four surfaces $S_1, S_2 ,S_3$ and $S_4$ are shown in figure. The flux emerging through surface $S_2$ in $N-m^2/C$ is

A square surface of side $L$ metres is in the plane of the paper. A uniform electric field $\vec E(V/m) $, also in the plane of the paper, is limited only to the lower half of the square surface, (see figure). The electric flux in SI units associated with the surface is

A few electric field lines for a system of two charges $Q_1$ and $Q_2$ fixed at two different points on the $\mathrm{x}$-axis are shown in the figure. These lines suggest that $Image$

$(A)$ $\left|Q_1\right|>\left|Q_2\right|$

$(B)$ $\left|Q_1\right|<\left|Q_2\right|$

$(C)$ at a finite distance to the left of $\mathrm{Q}_1$ the electric field is zero

$(D)$ at a finite distance to the right of $\mathrm{Q}_2$ the electric field is zero