Which of the following statements is true about the flow of electrons in an electric circuit?
Electrons always flow from lower to higher potential
Electrons always flow from higher to lower potential
Electrons flow from lower to higher potential, except through power sources
Electrons flow from higher to lower potential, except through power sources
Two spheres $A$ and $B$ of radius $a$ and $b$ respectively are at same electric potential. The ratio of the surface charge densities of $A$ and $B$ is
A charge of total amount $Q$ is distributed over two concentric hollow spheres of radii $r$ and $R ( R > r)$ such that the surface charge densities on the two spheres are equal. The electric potential at the common centre is
A hemispherical bowl of mass $m$ is uniformly charged with charge density $'\sigma '$ . Electric potential due to charge distribution at a point $'A'$ is (which lies at centre of radius as shown).
Assume that an electric field $\overrightarrow E = 30{x^2}\hat i$ exists in space. Then the potential difference $V_A -V_O$, where $V_O$ is the potential at the origin and $V_A$ the potential at $x = 2\, m$ is
Calculate potential on the axis of a ring due to charge $Q$ uniformly distributed along the ring of radius $R$.