A charge of $10\, e.s.u.$ is placed at a distance of $2\, cm$ from a charge of $40\, e.s.u.$ and $4\, cm$ from another charge of $20\, e.s.u.$ The potential energy of the charge $10\, e.s.u.$ is (in $ergs$)

Three charges $Q,( + q)$ and $( + q)$ are placed at the vertices of an equilateral triangle of side l as shown in the figure. If the net electrostatic energy of the system is zero, then $Q$ is equal to

In a hydrogen atom, the electron and proton are bound at a distance of about $0.53\; \mathring A:$

$(a)$ Estimate the potential energy of the system in $eV$, taking the zero of the potential energy at infinite separation of the electron from proton.

$(b)$ What is the minimum work required to free the electron, given that its kinetic energy in the orbit is half the magnitude of potential energy obtained in $(a)?$

$(c)$ What are the answers to $(a)$ and $(b)$ above if the zero of potential energy is taken at $1.06\;\mathring A$ separation?

An electron (charge = $1.6 \times {10^{ - 19}}$ $coulomb$) is accelerated through a potential of $1,00,000$ $volts$. The energy required by the electron is

What is the potential energy of the equal positive point charges of $1\,\mu C$ each held $1\, m$ apart in air

An $\alpha$ particle and a proton are accelerated from rest through the same potential difference. The ratio of linear momenta acquired by above two particals will be.