RE-NEET Physics Electrostatic Potential and Capacitance Class 12 Questions

Consider a fixed uniformly charged insulating sphere with radius R and total charge +Q. A point charge -q (q<<Q) with mass m is released from rest at a distance of 3R from the centre of the charged sphere. When the point charge reaches the surface of the sphere, its speed is : (ε₀ is the permittivity of vacuum, neglect gravitational forces).

A unit positive point charge is taken slowly through an infinitesimally thin tube that is inside a charged dielectric sphere of radius R, having uniform positive charge density ρ, as shown in the figure. The initial and final positions of the charge are marked by A and B at distances 2R and 3R respectively, from the centre of the sphere. In this process, the magnitude of the total work done on the point charge is $\frac{\rho R^2}{n \varepsilon_0}$. The value of n is ($\varepsilon_0$ is the permittivity of vacuum).

A point charge Q is placed inside a cavity within a solid isolated conducting sphere. Consider points A, B and C as shown in the figure, where the magnitudes of the electric fields are E_A, E_B and E_C respectively. The points B and C are at the same distance from the center of the solid sphere. The correct option is:

Three identical capacitors P, Q and S, each of the capacitance C, are connected to a battery of voltage V, as shown in the figure. If the energy stored in the capacitor P and total energy stored in the system are Uₚ and Uₜ, respectively, then the ratio Uₚ/Uₜ is:

A metal cube of side 5 cm is charged with 6 µC. The surface charge density on the cube is

A 12 pF capacitor is connected to a 50 V battery, the electrostatic energy stored in the capacitor in nJ is

The capacitance of a capacitor with charge q and a potential difference V depends on:

The value of electric potential at a distance of 9 cm from the point charge 4 × 10⁻⁷ C is