A pellet carrying a charge of $0.5$ coulomb is accelerated through a potential of $2000$ volts. It attains some kinetic energy equal to
$1000 \,erg$
$1000 \,joule$
$1000 \,kWh$
$500 \,erg$
If one of the two electrons of a $H _{2}$ molecule is removed, we get a hydrogen molecular ion $H _{2}^{+}$. In the ground state of an $H _{2}^{+}$, the two protons are separated by roughly $1.5\;\mathring A,$ and the electron is roughly $1 \;\mathring A$ from each proton. Determine the potential energy of the system. Specify your choice of the zero of potential energy.
A disk of radius $R$ with uniform positive charge density $\sigma$ is placed on the $x y$ plane with its center at the origin. The Coulomb potential along the $z$-axis is
$V(z)=\frac{\sigma}{2 \epsilon_0}\left(\sqrt{R^2+z^2}-z\right)$
A particle of positive charge $q$ is placed initially at rest at a point on the $z$ axis with $z=z_0$ and $z_0>0$. In addition to the Coulomb force, the particle experiences a vertical force $\vec{F}=-c \hat{k}$ with $c>0$. Let $\beta=\frac{2 c \epsilon_0}{q \sigma}$. Which of the following statement($s$) is(are) correct?
$(A)$ For $\beta=\frac{1}{4}$ and $z_0=\frac{25}{7} R$, the particle reaches the origin.
$(B)$ For $\beta=\frac{1}{4}$ and $z_0=\frac{3}{7} R$, the particle reaches the origin.
$(C)$ For $\beta=\frac{1}{4}$ and $z_0=\frac{R}{\sqrt{3}}$, the particle returns back to $z=z_0$.
$(D)$ For $\beta>1$ and $z_0>0$, the particle always reaches the origin.
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
The ratio of momenta of an electron and an $\alpha$-particle which are accelerated from rest by a potential difference of $100\, volts$ is
This questions has statement$-1$ and statement$-2$. Of the four choices given after the statements, choose the one that best describe the two statements.
An insulating solid sphere of radius $R$ has a uniformly
positive charge density $\rho$. As a result of this uniform charge distribution there is a finite value of electric potential at the centre of the sphere, at the surface of the sphere and also at a point out side the sphere. The electric potential at infinite is zero.
Statement$ -1$ : When a charge $q$ is take from the centre of the surface of the sphere its potential energy changes by $\frac{{q\rho }}{{3{\varepsilon _0}}}$
Statement$ -2$ : The electric field at a distance $r(r < R)$ from centre of the sphere is $\frac{{\rho r}}{{3{\varepsilon _0}}}$