Electric Potential & Energy of Systems — Practice Questions

Free NEET Physics multiple-choice questions on Electric Potential & Energy of Systems. Attempt each question and reveal the answer with a full explanation.

The variation of electrostatic potential with distance r from the centre of a thin spherical shell of radius R is correctly represented by: Constant from 0 to R , then decreasing as 1/r Zero from 0 to R , then increasing as r Increasing linearly from 0 to R , then constant Decreasing as 1/r 2 from 0 to infinity The work done in bringing a unit positive charge from infinity to a point in an electric field is the measure of: Electric potential Electric field Electric flux Capacitance Three charges Q, +q, +q are placed at the vertices of an equilateral triangle of side a . If the net electrostatic energy of the system is zero, then Q is equal to: -q/2 -q +q/2 -2q An electron moves through a distance of 6 cm in a uniform electric field of magnitude 2 10 4 N/C . The change in its potential energy is: 1.92 10 -16 J 1.12 10 -15 J 0.5 10 -16 J 1.92 10 -18 J Two charges +6 C and -4 C are placed 15 cm apart. At what distance from the +6 C charge (on the line joining them) is the electric potential zero? 9 cm 10 cm 5 cm 4 cm A point charge +q is placed at the center of a conducting spherical shell of inner radius a and outer radius b . The electric potential at a distance r from the center ( a < r < b ) is: 1 4 0 q b 1 4 0 q a 1 4 0 q r Zero A point charge Q is placed at the origin. The work done in taking another point charge q from point A(0, a) to B(a, 0) is: Zero Qq 4 0 a Qq 2 0 a Infinite The dimensional formula for electric potential is: [ML 2T -3 A -1 ] [ML 2T -2 A -1 ] [ML 3T -3 A -1 ] [ML 2T -3 A -2 ] The electric potential V at any point (x, y, z) in space is given by V = 4x 2 volt. The electric field E at the point (1 m , 0, 2 m ) in V/m is: 8 , along negative x-axis 8 , along positive x-axis 16 , along negative x-axis 16 , along positive x-axis An electron falls from rest through a vertical distance h in a uniform and vertically upward directed electric field E . The direction of electric field is now reversed, keeping its magnitude the same. A proton is allowed to fall from rest in it through the same vertical distance h . The time of fall of the electron, in comparison to the time of fall of the proton is: Smaller Greater Equal 10 times greater A bullet of mass 2 g having a charge of 2 μ C is accelerated through a potential difference of 10 kV . What will be its speed? 141.4 m/s 14.14 m/s 2 m/s 20 m/s The work done in moving a point charge q over an equipotential surface of potential V is: Zero qV V/q 2qV The electric potential at the center of a non-conducting charged sphere of radius R and total charge Q is: 1.5 times the potential at the surface equal to the potential at the surface zero 2 times the potential at the surface Two charges q 1 and q 2 are placed 30 cm apart, as shown in the figure. A third charge q 3 is moved along the arc of a circle of radius 40 cm from C to D . The change in the potential energy of the system is q 3 4 0 k , where k is: 8q 2 8q 1 6q 2 4q 1 A charge Q is distributed over two concentric hollow spheres of radii r and R ( R > r ) such that the surface charge densities are equal. The potential at the common center is: 1 4 0 Q(R+r) R 2+r 2 1 4 0 Q R+r 1 4 0 Q(R-r) R 2+r 2 Zero 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 , as shown in the figure. The initial and final positions of the charge are marked by A and B at distance 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 R 2 n 0 . The value of n is: ( 0 is the permittivity of vacuum) 2 6 9 18 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: ( 0 is the permittivity of vacuum, neglect gravitational forces). 3Qq 4 0 mR 2Qq 3 0 mR Qq 3 0 mR Qq 4 0 mR The energy density (energy per unit volume) in a parallel plate capacitor is given by: 1 2 ε 0 E 2 1 2 ε 0 2 E ε 0 E 2 1 2 E 2/ε 0 A point charge q is rotated along a circle in the electric field generated by another point charge Q . The work done by the electric field on the rotating charge is: Zero Positive Negative Dependent on radius The electric potential V as a function of distance x (in metres) is given by V = (5x 2 + 10x - 9) Volt. The value of electric field at x = 1 m is: -20 V/m 6 V/m 11 V/m -23 V/m A particle of mass m and charge q is released from rest in a uniform electric field E . The kinetic energy attained by the particle after moving a distance y is: qEy qE 2y qEy 2 qEy m The energy density in a region of electric field E is proportional to: E 2 E 1/E 1/E 2 The electric potential V at any point (x, y, z) in space is given by V = 4x 2 volt . The electric field E at point (1 m , 0, 2 m ) in V/m is: 8 along negative x-axis 8 along positive x-axis 16 along negative x-axis 16 along positive x-axis The electrostatic potential energy of a system of two charges q 1 and q 2 separated by distance r is given by: 1 4 0 q 1q 2 r 1 4 0 q 1q 2 r 2 - 1 4 0 q 1q 2 r Zero