Level 3

Two small charged spheres have charges of $2\times {10}^{-7}\mathrm{C}$ and $3\times {10}^{-7}\mathrm{C}$. They are placed $30 \mathrm{cm}$ apart in air. What is the force between them?

Positive point charges are placed at the vertices of a star shape as shown in the figure. Direction of the electrostatic force on a negative point charge at the centre $O$ of the star is

Two equal and opposite charges are placed at points $P$ and $Q.$ The null point on the line joining them is

For section $AB$ of a circuit shown in figure, $C_1=1 \mathrm{\mu F},C_2=2 \mathrm{\mu F},E=10 \mathrm{V}$, and the potential difference $V_A-V_B=-10 V$. Charge on capacitor $C_1$ is:

Two capacitors $C_1$ and $C_2$ are charged to $120 \mathrm{V}$ and $200 \mathrm{V}$, respectively. It is found that by connecting them together the potential on each one can be made zero. Then

In figure the initial status of capacitors and connections is shown. Which of the following is incorrect about this circuit?

In the given circuit, a charge of $+80 \mathrm{\mu C}$ is given to the upper plate of the $4 \mathrm{\mu F}$ capacitor. Then in the steady state, the charge on the upper plate of the $3 \mathrm{\mu F}$ capacitor is

An electron travelling in a uniform electric field passes from a region of potential $V_1$ to a region of higher potential $V_2$. Then