There is $10$ units of charge at the centre of a circle of radius $10\,m$. The work done in moving $1\, unit$ of charge around the circle once is...........$units$

A particle of mass $m$ and charge $q$ is kept at the top of a fixed frictionless sphere. $A$ uniform horizontal electric field $E$ is switched on. The particle looses contact with the sphere, when the line joining the center of the sphere and the particle makes an angle $45^o$ with the vertical. The ratio $\frac{qE}{mg}$ is :-

When a positive $q$ charge is taken from lower potential to a higher potential point, then its potential energy will

A pellet carrying a charge of $0.5$ coulomb is accelerated through a potential of $2000$ volts. It attains some kinetic energy equal to

A uniformly charged thin spherical shell of radius $\mathrm{R}$ carries uniform surface charge density of $\sigma$ per unit area. It is made of two hemispherical shells, held together by pressing them with force $\mathrm{F}$ (see figure). $\mathrm{F}$ is proportional to

A block of mass $m$ containing a net negative charge $-q$ is placed on a frictionless  horizontal table and is connected to a wall through an unstretched spring of spring  constant $k$ as shown. If horizontal electric field $E$ parallel to the spring is switched on,  then the maximum compression of the spring is :-