Electric Field and Potential Questions and Answers

7 Calculate the electric field intensity near an infinitely long chared plane conductor having surface density of charge 0 5 stat coul cm 8 calculate the equivalent capacity in the given figure across the point i M and N ii across the points M and C

Try Yourself 44 An early model for an atom considered it to have a positively charged point nucleus of charge Ze surrounded by a uniform density of negative charge upto a radius R The atom as a whole is neutral For this model what is the electric field at a distance r from the nucleus

11 A deuteron and an x particle are placed in an electric field The force acting on them are F and F and their accelerations are a and a respectively then 1 F F F1 F2 2 F F 3 a a N

Consider two semi infinite flat plates lying parallel to the ry plane at z d and z d carrying uniform surface charge densities to and respectively The plates extend from z 0 to r x and from y x to y o The direction of the electric field at a point whose coordinates are 0 0 2d is along Options

Three infinitely long linear charges of charge density A A and 2 A are placed in space A point in space is specified by its perpendicular distance r 12 13 respectively from the linear charges For the points which are equipotential 11 12 constant r 23 constant 1 2 11213 constant 1 23 constant

Zero Marks 0 In all other cases During lighting a current pulse shown in figure flows from the cloud at a height 1 5km to the ground If the breakdown electric field of humid air is about 400 kVm the energy released during lighting would be in unit of 109 J I KA 150 0 0 2 ms

2 4 Will be infinite An electric dipole is placed at the centre of a sphere select the correct option 1 The electric field is zero at every point of the sphere 2 The flux of the electric field through the sphere is zero 3 The electric field is not zero at anywhere on the sphere 4 Both 2 and 3 In the region of space the electric field is given by

should be 5 AIIMS 2011 d 1 4 uted over a electric field AIIMS 2009 q d 2 TER Two parallel large thin metal sheets have equal surface charge densities o 26 4 x 10 12C m of opposite signs The electric field between these sheets is a 1 5 N C c 3 N G d 3 10 10 N C x 15 The spatial distribution of the electric field AIIMS 2006 b 1 5 x 10 10 N C

A positively charged particle moving along x axis with a certain velocity enters a uniform electric field directed along positive y axis Its x axis Horizontal y axis Vertical 1 Vertical velocity changes but horizontal velocity remains constant 2 Horizontal velocity changes but vertical velocity remains constant 3 Both vertical and horizontal velocities change 4 Neither vertical nor horizontal velocity changes

Studying 14 A charge q is placed at the centre O of cobe of length L Another same charge q is placed at a distance L from O Then electric flux through face ABCD is E herm mender H q 1 ATEL 29 3 2 EL q B L D A 9 q 2 2TEL 4 Zero th

M CAPS 02 Physics Two charges exert a force of 10 N on each other when separated by a distance 0 2 m in air When they are placed in another medium of dielectric constant K 4 and separated by distance R they exert same force The distance R equals to 1 2 m 2 1 m 3 0 2 m 4 0 1 m The electric field at origin due to infinite number of in figure is Carry Forward The force of repulsi is F when these a Now the point cha radii 25 cm havi point charges an new force of rec 1 Increases 2 Decrease

3 Which of the following is a vector quantity 1 Electric Field Intensity 2 Electric Potential 4 Electric Charge 3 Electric Current 4 Two wires A and B are having lengths of 40 cm and 30 cm respectively Both of them are bent in th

A positive charge 50 C is located in xy plane at a position vector 41 41 The electric field strength E at a point whose position vector is 7 101 4 is 7 and 7 are expressed in metre 1 1 6i 3 6 kV m 2 3 6 1 6 kV m 3 i 3 kV m 4 2 71 3 61 kV m

In the very last line it is written that but the electric field on the surface of charged conductor is not zero does it m ean that it is Sigma by Epsilon not which may be positive or negative and is the unit vector normal to the surface in the outward direction Electrostatic Shielding In an electrostatic situation if a conductor contains a cavity and if no charge is present inside the cavity then there can be no net charge anywhere on the surface of the cavity This means that if you are inside a charged conducting box you can safely touch any point on the inside walls of the box without being electrocuted This is known as electrostatic shielding Remember the following facts i There is no net charge anywhere on the surface of the cavity i e o 0 The potential inside or on the surface of the cavity The potential inside the material of the conductor The potential on the surface of the conductor V constant i The electric field in or on the surface of the cavity The electric field inside material of the conductor 0 0 E 0 0 E V V V V constant E 0 0 0 0 0 V V constant E 0 E 0 xxxxxx E 040 a O E conducting body zero But the electric field on the surface of a charged conductor is not zero Figure shows an uncharged conductor in an external electric field E 0 The free electrons in the conductor distribute themselves on the surface ao chown in the funcion

8274 An infinite number of identically charged bodies are kept along the x axis at points x 0 1 m 2 m 4 m 8 m 16 m and so on All other charges repel the charge at the origin with a force of 1 2 N Find magnitude of each charge a 9 C b 10 C F KQ 0 c II C d 12 C If the met electric flue through a closed surfa 82 02 2

36 Figure shows some equipotential lines distributed in space A charged particle is moved from point A to point B 10V 30V B TATAL ERI 10V 20V 30V 40V 50V 20V 40V 50V Field I Field II a The work done in field I is greater b The work done in field I is smaller c The work done is the same in field I and field d The work done is zero in field I and is positive in field II

An uncharged thin spherical metallic shell of radius R has a positive charge q at its centre A second positive charge Q is placed outside the shell at a distance r from the centre of the shell The force experienced by the charge q is A zero B C D qQ 2 4 r qQ 4 r 2 qQ ATC R radially inward radially outward radially outward

6 An infinitely long line charge having a uniform charge per unit length lies a distance d from center of imaginary sphere of radius R Then a flux crossing the sphere is zero if d R a b c d 22 R d b flux crossing the sphere is if d R E0 c If d R the magnitude of maximum potential difference between two points on the sphere is 2 In d R d R 2 0 d When a charge is moved along any diameter of the sphere in the plane perpendicular to the wire work done is zero

Q26 A 2 5 x 107 C at A 0 0 15 cm qB 2 5 x 10 7 Cat B 0 0 15 cm Find electric dipole moment of system a 7 5 x 10 7 R Cm b 7 5 x 10 7 R Cm 7 5 x 10 8 R Cm C z VB tc ve

A particle of mass m and charge q is placed a rest in a uniform electric field E and ther released The kinetic energy attained by the particle after moving a distance y is 1998 B qE y D q Ev A qEy oFv

9 he force between two small charged spheres having charges of 1 x 10 7 C and 2 10 7C placed 20 cm apart in air is 1 Point 4 5 10 2 N 4 5 x 10 3 N 5 4 x 10 2 N 5 4 x 10 3 N 10 If the dipole of moment 2 57 x 10 17 cm is placed into an electric field of magnitude 3 0 x104 N C such that the fields lines are aligned at 30 with the line joining P to the dipole what torque acts on the dipole 1 Point 7 7 x 10 13 Nm 3 855 x 10 13 Nm 3 855 10 15 Nm 7 7 x 10 15 Nm

An electric charge 10 3 C is placed at the origin 0 0 of x y coordinate system The two points A and B are situated at 2 2 and 2 0 respectively The potential difference between the points A and B will be a 4 5 v c Zero b 9 v d 2 v

to get a total charge of 1 C on the other body 12 How much positive and negative charge is there in a water molecule 13 A conductor has 14 4 x 10 19 C positive charge The conductor has charge on elec

Previous Years Questions bash emiyonada A spherical conductor of radius 10 cm has a charge of 3 2 x 10 7 C distributed uniformly What is the magnitude of electric field at a point 15 cm from the centre of the sphere 1 9x109 Nm C NEET 2020 Phase 1 Fran Glic all 4t Eo 1 1 28 x 105 N C 3 1 28 x 107 NIC 2 1 28 106 N C X

11 An electric dipole of moment p is placed in an electric field of intensity E The dipole acquires a position such that the axis of the dipole makes an angle 0 with the direction of the field Assuming that the potential energy of the dipole to be zero when 0 90 the torque and the potential energy of the dipole will respectively be AIPMT Prelims 2012 1 pE sine 2pE cose 2 pE cose pE sine nE sing nF cose 4 pe sine 2pE cosf 2

A particle having a charge q 1C and mass m 0 5 kg is projected on a rough horizontal plane x y from a point 15m 0 0 with a initial velocity v 20 j In space an uniform electric field E 25 k and magnetic field B 10 k The acceleration due to gravity g 10 msec 2 and co efficient of friction 0 5 The particle moves on a spiral path and reaches to the origin The time taken by particle to reach origin is found y x 10 sec Find y

charged particles each a charge of q are located along the x axis at x 2 and x 4 as shown below Which of the following shows the graph of the magnitude of the electric field along the x axis from the origin to x 6 1 2 3 4 E 3 5 6 LIVE DING 2 3 E 1 or 1 q 2 1 3 2 co q 4 X 6 5 1 2 3 5 6 5 6 1 2 3 4 5 6 X

and C of radi arge density are kept at pacitors 31 Three point charges q 2q and 2q are placed at the vertices of an equilateral triangle of side a The work done by some external force to increase their seperation to 2a slowly will be 1 2q 1 Are a 3 4 1 8q a 1 q 2 4 2a 4 Zero

6b A long straight wire has fixed negative charge with a linear charge density of magnitude 3 6 nC m The wire is to be enclosed by a coaxial thin walled nonconducting cylindrical shell of radius 1 5 cm The shell is to have positive charge on its outside surface with a surface charge density o that makes the net external electric field zero Calculate

1 Diagram shows symmetrically placed rectangular insulators with uniformly charged distributions of equal magnitude At the origin the net field E is net 1 aligned with the negative x axis 2 aligned with the negative y axis 3 aligned with the positive y axis 4 aligned with the positive x axis

Example 1 5 A Parallel plate capacitor having a plate separation of 2 x 103 m across which a potential of 10V is applied Calculate the delectric displacement when a material of dielectric content 6 0 is introduced between the plates

7a A nonconducting sphere has radius R 2 31 cm and uniformly distributed charge q 3 50 fC Take the electric potential at the sphere s center to be Vo 0 What is V at radial distance a r 1 45 cm and b r R

with radius a and a charge Q on the outer shell with radius b Find V V the difference in potential on the surfaces of the two spheres kQ b Zero b KQ a O a KQ KQ a b III II kQ I I

A region of space has an electrostatic field E x y z x 4yx y zy z 3xz and an electrostatic potential V 0 at the origin 1 Calculate the charge density p x y z 2 Calculate the electrostatic potential V x y z

7b What are a the charge and b the charge density on the surface of a conducting sphere of radius 0 15 m w potential is 200 V with V 0 at infinity

25 A point Q lies on the perpendicular bisector of an electrical dipole of dipole moment p If the distance of Q from the dipole is r much larger than the size of the dipole then the electric field at Q is proportional to 1 p r 3 3 p r 2 p r 2 4 p r

A parallel capacitor is filled with an insulator and a certain potential difference is applied to its plates The energy stored in the capacitor is U Now the capacitor is disconnected from the source and the insulator is pulled out of the capacitor The work performed against the forces of the electric field in pulling out the insulator is 4U The dielectric constant of the insulator is

49 Two long thin charged rods with charge density each are placed parallel to each other at a distance d apart The force per unit length exerted on one rod by the other will be where k 1 C K2 d K22 2 K22 d k2 1 4TEO

near charge Two parallel infinite densities C m and 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 3 2 TEOR N C 2 N C TER NEET 2019

Two large vertical and parallel metal plates having a separation of 1 cm are connected to a DC voltage source of potential difference X A proton is released at rest midway between the two plates It is found to move at 45 to the vertical just after release Then X is nearly 2012 a 1 10 5 v b 1x 107 V c 1 10 V d 1x 10 0 V 11

four charges each of Q Q Q and Q are placed at the corner of a square of side L calculate the resultant electric intensity at P the center of the square compare the acceleration produced in electron and proton if they are placed in the same electric field

Find out the surface charge density of infinite thin metalic sheet parallel to yz plane passing through x 8 If net field at x 3 is zero due both sheet and infinite line charge of 8 nC m lying along the z axis 0 62 nC m 0 52 nC m 0 42 nC m 0 32 nC m

6 Two wires of equal diameters resistivities an p and lengths x and x respectively are joine in series The equivalent resistivity of th combination is 1 3 P X P X X X P X P X X X 2 4 P X P X X X P X P X X X

1 If a point charge q is placed at a point inside a hollow conducting sphere then which of the following electric lines of force pattern is correct a distanc d None of these If they are released the kinetic energy of

Consider the arrangement of charges on the vertices of a square as shown in the figure The net electrostatic potential at the centre of the square will 1 mC 2 mC be 2 m 1 MC O 0 69 V O 0 5 V O 2V O Zero 2 mC

1 Identify three closed curves in the triangular pyramid shown in fig 1 State which sides form an open surface for which one of these closed curve is the boundary Dose this figure has any closed surface 4 Fig 1

The potential of electric field V x2y where x and y denotes coordinate of a point in electric field region Which of the following is incorrect Electric field at all points on positive x axis is in positive y direction Electric field at all points on positive y axis is in negative x direction Electric field at origin is non zero Electric field at x y makes an angle of 0 cot 7 with x axis

Consider an infinitely large thick charged non conducting sheet in some external electric field as given 3 3 E Volume charge E The electrostatic pressure experience by sheet a does not depend on thickness of plate b does not depends on volume charge distribution c depends on field E and E d Depends on thickness as well as volume charge distribution

2 Two sets of equipotential surfaces A B are shown in the Fig 2 o i 1 2 3 are the potentials of these surfaces Which of the set has higher value for electric field Give reasons for your answer F14 2

1 EXERCISE III SINGLE CORRECT ANSWER QUESTIONS n conducting plates are placed face to face Distance between two consecutive plates is d Area of plates is A A A C A 24 8 2 A dielectric slab of dielectric constant ki inserted between the first and secon plates and the assembly is charged by a batter of emf x Find the charge stored in th assembly A5 A 2d 2 1 A af k A 2 A 4 H 2 2 B 2d A5 1 2 1 A5 1 2 2 D 3d 2 2 k A