Charges $Q_1$ and $Q_2$ are at points $A$ and $B$ of a right angle triangle $OAB$ see figure. The resultant electric feild at point $O$ is perpendicular to the hypotenuse, then $Q_1/Q_2$ is proportional to :

Q. Assertion :Four point charges $q_1$, $q_2$, $q_3$ and $q_4$ are as shown in figure. The flux over the shown Gaussian surface depends only on charges $q_1$ and $q_2$. Reason: Electric field at all points on Gaussian surface depends only charges $q_1$ and $q_2$.

Q. The electric field lines for a system of two charges $Q_1$ and $Q_2$ fixed at two different points on the $\text{x-}$axis are as shown in the figure. Then $\frac{Q_1}{Q_2}$ might be

Q. A charge $Q$ located at a point $\overrightarrow{r}$ is in equilibrium under the combined electric field of three charges $q_1,q_2,q_3$. If the charges $q_1,q_2$ are located at points ${\overrightarrow{r}}_1$ and ${\overrightarrow{r}}_2$ respectively, find the direction of the force on $Q$, due to $q_3$ in terms of $q_1,q_2,{\overrightarrow{r}}_1{\overrightarrow{r}}_2$ and $\overrightarrow{r}$.

Q. Assertion$\left(A\right)$: Four point charges $q_1,q_2,q_3$ and $q_4$ are as shown in figure. The flux over the shown gaussian surface depends only on charges $q_1$ and $q_2$

Reason$\left(R\right)$: Electric field at all points on gaussian surface is depends only on charges $q_1$ and $q_2$


Select the most appropriate answer from the options given below

Q. Two positive charges $q_1$ and $q_2$ are moving with velocities $v_1$ and $v_2$ when they are at points $A$ and $B$, respectively, as shown in figure. The magnetic force experienced by charge $q_1$ due to the other charge $q_2$ is :