An infinitely large layer of charge of uniform thickness $t$ is placed in existing uniform electric field. Presence of this charged layer so alters the electric field that it remains uniform on both the sides and assumes values $E_1$ and $E_2$ as shown in figure. If, $\left|{\overrightarrow{E}}_2\right|=20 \mathrm{N} {\mathrm{C}}^{-1}$ Then component of external field in $x$-direction (in $\mathrm{N} {\mathrm{C}}^{-1}$) is

Two charged particles $\mathrm{q}$ and $4\mathrm{q}$ are kept at distance $3 \mathrm{m}$ as shown in figure,

The force on a charge $\mathrm{Q}$ kept at $\mathrm{P}$ is

In the given figure, if $Q_1$ and $Q_2$ are positive, where could a negative charge be placed to have vertically upward net force on it?

In the given figure, if the vertical distance from point $E$ to $B$ is the same as the horizontal from $D$