Recent questions and answers in Electrostatics

A 5 $\mu$F capacitor is charged fully by a 220 V supply. It is then disconnected from the supply and is connected in series to another uncharged 2.5 $\mu$F capacitor. If the energy change during the charge redistribution is $X\over100$ J then value of X to ...

A charged particle (mass m and charge q) moves along X axis with velocity V0. When it passes through the origin it enters a region having uniform electric field $\vec{E}=-E\hat{j}$ which extends upto x = d. Equation of path of electron in the region x > d ...

A parallel plate capacitor having cross-sectional area A and separation d has air in between the plates. Now an insulating slab of same area but thickness d/2 is inserted between the plates as shown in figure having dielectric constant K(= 4). The ratio of ...

A charge Q is distributed over two concentric conducting thin spherical shells radii r and R (R > r). If the surface charge densities on the two shells are equal, the electric potential at the common centre is : (1) ${1\over4\pi\epsilon_0}{(2R+r)\over(R^2+r...

The variation of electrostatic potential with radial distance r from the centre of a positively charged metallic thin shell of radius R is given by the graph

The acceleration of an electron due to the mutual attraction between the electron and a proton when they are 1.6 Å apart is : (me = 9 10−31 kg, e = 1.6 10−19 C) (Take $1\over4\pi\epsilon_o$ = 9 109Nm2C−2) (1) 1025 m/s2 (2) 1024 m/s2 (3) 1023 m/s2 (4) ...

A 10µF capacitor is fully to a potential difference of 50 V. After removing the source voltage it is connected to an uncharged capacitor in parallel. Now the potential difference across them becomes 20 V. The capacitance of the second capacitor is : (1) ...

The electric field at a point on the equatorial plane at a distance r from the centre of a dipole having dipole moment $\vec{p}$ is given by, (r >> separation of two charges forming the dipole, $\epsilon_0$ - permittivity of free space) (1) $\vec{E}=-{\vec{...

A parallel plate capacitor of capacitance 20 $\mu$F is being charged by a voltage source whose potential is changing at the rate of 3 V/s. The conduction current through the connecting wires, and the displacement current through the plates of the capacitor,...

What is the definition of coulombs law of electrostatics

The capacitance of a parallel plate capacitor with air as medium is 6 µF. With the introduction of a dielectric medium, the capacitance becomes 30 µF. The permittivity of the medium is : ($\epsilon_0$=8.85 10-12 C 2 N-1m-2) (1) 5.00 C2N-1m-2 (2) 0....

A spherical conductor of radius 10 cm has a charge of 3.2 10-7 C distributed uniformly. What is the magnitude of electric field at a point 15 cm from the centre of the sphere ? $\left({1\over4\pi\epsilon_0}=9 10^9 N m^2/C^2\right)$ (1) 1.28 107 N/C (2) ...

An oil drop is found floating freely between the plates of a parallel plate capacitor, the plates being horizontal and the lower plate carrying a charge of +Q. The area of each plate is A and distance of separation between them is D. The mass of the oil ...

For a uniformly charged ring of radius R, the electric field on its axis has the largest magnitude at a distance h from its centre. Then value of h is : (1) $R\over\sqrt5$ (2) $R$ (3) $R\over\sqrt2$ (4) $R\sqrt2$

Two parallel infinite line charges with linear charge densities $+\lambda$ C/m and $-\lambda$ C/m are placed at a distance of 2R in free space. What is the electric field mid-way between the two line charges? (1) Zero (2) $2\lambda\over\pi\epsilon_0R$ N/C (...

A parallel plate capacitor is made of two square plates of side 'a', separated by a distance d (d<<a). The lower triangular portion is filled with a dielectric of dielectric constant K, as shown in the figure. Capacitance of this capacitor is : (1) ${1\...

Three charges +Q, q, + Q are placed respectively, at distance, 0, d/2 and d from the origin, on the x-axis. If the net force experienced by + Q, placed at x= 0, is zero, then value of q is : (1) +Q/2 (2) –Q/2 (3) –Q/4 (4) +Q/4

Two point charges A and B, having charges +Q and -Q respectively, are placed at certain distance apart and force acting between them is F. If 25% charge of A is transferred to B, then force between the charges becomes : (1) $F$ (2) $9F\over16$ (3) $16F\...

A hollow metal sphere of radius R is uniformly charged. The electric field due to the sphere at a distance r from the centre (1) Increases as r increases for r < R and for r > R (2) Zero as r increases for r < R, decreases as r increases for r > R (3) Zero ...