Electric Field and Potential Questions and Answers

An AC circuit having supply voltage E 100 sinot all quantities are in SI units consists of a resistor of 300 and an inductor of reactance 400 as shown in the figure Find the magnitude of voltage across the inductor at t s in V T 00 roo ww

A 500 eV electron is fired directly towards a large metal plate having surface charge density 8 85 x 106 Cm 2 The distance from where electron be projected so that it just fails to strike the plate is O 0 2 mm O 0 33 mm O 0 5 mm O 1 21 mm

A thick shell with inner radius R and outer radius 3R has a uniform charge density o c m It has a spherical cavity of radius R as shown in the figure The electric field at the centre of the cavity is 1 zero 3 30R 48 3R Cavity 2 20R 80 4 70R 1280

Two identical thin metal plates has potential V and V V V A neutral metal slab is place between these two plates Find potential of righ surface of metal slab xrd x 2d x 3d x 5d 1 V V 3 1 V V 2 2V V 3 V 2V

Magnetic field at point O due to the given structure is i H 1 1 k Hoi 4a H k 2a Ho 2a a D 1 k

A uniformly charged semi infinite wire having linear charge density 2 x 10 10 C m is placed along x axis as shown Find electric flux in Sl units through a ring of radius r 10 cm centred at origin O and lying in y z plane 0

The electric potential difference between two parallel plates is 1000 V If the plates are separated by 2 mm what is magnitude of electrostatic force on a charge 2 x 10 6C located midway between plates 01 N 02N 4 N O 0 2 N

10 A molecule of a substance has a permanent electric dipole moment of magnitude 10 20 C m A mole of this substance is polarised at low temperature by applying a strong electrostatic field of magnitude 10 V m The direction of the field is suddenly changed by an angle of 60 Estimate the heat released by the substance in aligning its dipoles along the new direction of the field For simplicity assume 100 polarisation of the sample INCERT Solved Example Ans 3 01 11 Charges of 1 2 x 10 8 C and 1 6 x 10 8 C are placed at two points and I

A ring of radius r carries a charge Q uniformly distributed over its length A charge q is placed at its centre will experience a force equal to Question Type Single Correct Type 1 2 3 qQ 4 TEOR qQ 8 r zero

25 V 292 Answer A B C D www 10023 Your Attempt www 5923 1 0v 10 V T12 Correct answer the current through 10ohm is 2 A the current through 5ohm is 2 5 A the current through 25 V battery is 6 25 A the potential difference between the terminals of 10V batte

Two charges 50 C and 2 5 C are 20 cm apart as shown in figure Th work done in displacing charge 2 5 C from point B to C is A 50 C 20 cm O 3 2 J O 1 12 J O 1 5 J 0 25 1 90 15 cm B 2 5 C

A charge Q is distributed uniformly on a ring of radius R A point charge q is placed on axis at distance 2R from centre of the ring The force experienced by point charge at given position is O Zero Qq 8R2 Qq 16 5R2

direction of electric field SV 10 V 15 V 20 V 1 42 3 4 cm O 10 V m along positive x axis O 5 V m along positive y axis O 50 V m along negative x axis O 500 V m along negative x axis

A short electric dipole of dipole moment 12 C m is placed along x axis with its centre at origin The electric potential at a point 4 0 m due to given dipole is O 2 25 kV O 6 75 kV 04 kV 9 50 kV

Two parallel infinite line charges A and are placed at a separation 2a in free space The net electric field intensity exactly midway between two line charges is Zero 2 Ta 2 2 22

f charge on a body is 2 nC then how many electrons are absent from Dody 01 5 1027 01 25 1028 1 25 1010 01 6 1019

A bob of mass m is tied with a thread and is made to move in a circular path on a horizontal frictionless table about point O as shown in the figure A hypothetical electric field exists in the radial direction along the surface of the table In this condition the bob is uncharged and the tension in the thread is T If now the bob is given some charge then V m TE

A particle of mass m and charge q starts moving from rest along a straight line in an electric field E Eo ax where a is a positive constant and x is the distance from starting point Find the distance travelled by the particle till the moment it came to instantaneous rest E 2 E a c a E og b 3 d a Eo

Figure shows the variation of electric field intensity E versus distance x The magnitude of potential difference between the points x 0 to x 5 mis 10 E N C 0 2 O 30 volt O 60 volt O 40 volt 6 x m

in electron is placed at its corners of a regular 69 Force on the short dipole due to the point charge be kept on the equator of the dipole in the configuration shown in the figure is 3q FI D E 20 29 2 Along OF 4 None of these the vertices of a regular as shown in the figure 1 Zero Q Qqa 3 2 d d 2 q 2a Qqa TEO d Qqa d 4 o through a sphere due to a

A charge particle having charge 4 x 10 3 C moves from state of rest in uniform electric field of magnitude 5 x 103 V m What is its KE after 10 second m 2 10 kg O 1013 J O 10 J 05 x 1012 J O 1014 J

Two identical thin rings each of radius 10 cm carrying charge 10 C and C are co axially placed at distance 10 cm apart The work done in moving a charge q from the centre of first ring to that of second ring is 9 2 1 41 0 q 870 q 8 TEO 9 4TEN 2 10 J 1 1 2 x 10 J 2 1 2 1 10 J x10 J

shell of radius 20 cm A charge Q 20 C is given to the inner sphere now inner sphere is connected to the shell by a conducting wire the amount of heat generated in process is 06 J 09J 12 J O 14 J

Initially two charged particles A and B are moving with same velocity along x axis when uniform electric field is applied in that region Velocity of A changes its direction by 60 and speed is doubled direction of B changes by 30 then ratio of specific charges

The bob of mass m charge q is circulating in a verticle circle of radi us r with the help of a string If the max speed of the bob is v then t he period of revolution is T1 If an electriv field of magnitude mg q i s setup which makes an angle 60 degree with upward verticle agai n the bob is circulating in same circle and its max speed is also v th en the period of rev is T2 Find T1 T2

66 Two equal resistances are connected in the gap of a metre bridge If the resistance in the left gap i increased by 10 the balancing point shift 2 10 to left 4 4 8 to right 1 10 to right 3 96 to right

A parallel plate capacitor is connected from a cell and then isolated from it Two dielectric slabs of dielectric constant K and 2K are now introduce in the region between upper half and lower half of the plate as shown in figure The electric field intensity in upper half of dielectric is E and lower half is E2 then 1 E 2E Question Type Single Correct Type 2 3 K E 4 2K E Electrostatic potential energy of upper half is less than that of lower half Induced charges on both slabs are same Charge distribution on the plates remains

Mark the INCORRECT option s A If d e f and f d e then d and are opposite in direction B If d ef and f 2d d e then d and e are perpendicular C If d e f and f d e then d and are in the same direction D If d e f and f 2d d e then d and are in opposite direction

Q1 An infinite number of identically charged bodies are kept along the x axis at points x 0 1m 2m 4m 8m 16m 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 9uC B 10 C c 11 C d 12 C

For x R we know that the electric fo rce due to the uniformly charged ring is restoring in nature and we can also see that the force is proportional to the dis placement x Hence the particle will ex ecute SHM

92 L x Corigin 9 8 Two charges q 12 C and q 13 C are positioned different coordinates as shown in the figure Coordinate of q charge is b a and that 91 harge is b a Find the net electric field at the origin in unit vector notation Assume that a 7 m and b 2 m Here C denotes coulombs

3 3 ak Find the force between an infinite earthed conductor and a point charge placed at perpendicular distance x from earthed conductor shown in figure 1 1 q 2 4 x 3 zero 19 L2x 470 4x BAG 012 4 A 4 8 4x 86 sitt magsib ontwoliot JA 29 2 x tres opens irllog a avor of Snob Sd X

6 In a regular polygon of n sides each corner is at a distance r from the centre Identical charges are placed at n 1 corners At the centre the intensity is E and the potential is V The ratio of V E has magnitude 1 m 2 r n 1 3 n 1 r 4 r n 1 n Mon

5 Charges are given to three large parallel conducting plates as shown in figure Now the switch S is closed The value of electric field between the plates 2 and 3 is each plate has surface of Area A 1 3 10 C 1 30 C A Eo 20 C AF blor 2 20 C 1 30 C 4 zero S 25 C 2 A Eo ontbale

2 27 A non conducting sphere of radius R 5 cm has its centre at origin O of co ordinate system It has a spherical cavity of radius r 1 cm having its centre at 0 3 cm Solid material of sphere has uniform positive 10 charge density p coulomb m The potential at TC

25 A charge Q is uniformly distributed through out the volume of a dielectric sphere of radius R If potential at its surface is 24 volts Then potential 3R R 2 and r respectively are 2 where r distance from the centre of sphere 1 36V 12V 2 33V 16V 3 16V 12V 4 20V 10V at r

For a finite line charge the net electric field at the non axial point P is directed toward the line PQ where PQ makes an angle with the axis of line charge Find the value of 0 Q 0 PO 13m A B 4 m 3m C A B 4m 3m tan 10 tan 2 O tan 14 O i3m tan 26

18V 6 F HH www 602 In the given circuit b a 3 F 302 The potential of a point a with respect to b V Vb is 6 V a The charge that flows through the switch S when it is closed is 54 C Final potential of b with respect to ground is 6 V after switch is closed Change in energy stored in 6 F capacitor is 324 J after switch is closed

Two parallel metallic plates each of area A are kept as shown in the figure and charges 2Q and 4Q are given to them Edge effects are negligible The charges on the surfaces I and III are 4Q 2Q 1 2Q 2Q 3 Q 3Q III IV 2 Q 3Q 4 2Q 3Q

Electric dipole of moment P P is kept at a point x y in an electric field E 4 xy 4 x y j Find the forces on the dipole laborood particle which is

A circular ring of radius R with uniformly distributed positive charge Q on its circumference is located in xy plane with its centre at origin O A particle of mass m and charge q is at origin It is slightly disturbed towards z axis Kinetic energy when it reaches at z R 3 wong 2010 cu 1 31 KqQ 2R KqQ 2 4 199 KqQ R ASV 0 KqQ

Two similar point charges q are kept 2 points separated by a distance 2d in air Now an earthed conducting sphere of radius a is placed midway between them If d a what will be the condition when the sphere just neutralizes the repulsive force existing between the point charges a d 4 O a d 8 a d O a d 2

A conducting sphere S of radius r is attached to an insulating handle Another conducting sphere S of radius R is mounted on an insulating stand S is initially uncharged S is given a charge Q brought into contact with S and removed S is recharged such that the charge on it is again Q and it is again brought into contact with S and removed This procedure is repeated n times a Find the electrostatic energy of S after n such contacts with S b What is the limiting value of this energy as n

18 4 1 0 Three equal charges are placed at the three corners of an isosceles triangle as shown in figure The statement which is true for electric potential V and the field intensity E at the centre of the triangle is

A vertical thick conducting wall has a constant surface charge density o c m A point object of charge q and mass m is hanging from the wall as shown in the figure The thread connecting the object and the wall is non conducting the massless At equilibrium the tension in the thread is q

PLEASE EXPLAIN IN DETAIL The electric field at a point A is perpendicular to the direction of dipole moment p of a short electric dipole The angle 8 is tan 2 r tan 2 tan 1 0

The electric field in a region of space is 1 4j 3k kN C The electric flux due to this field over an area i 1 m is 2 x 103 N m C 1 4 x 10 N m C 1 3 x 10 N m C 1 3 x 10 N m C 1

Problem 1 15pts Consider the conducting sphere of radius R and charge Qo shown in the figure below The conducting sphere is located in the interior of a spherical shell of internal radius R and external radius R R R The inside of the spherical shell has a charge Q Q 2 whose charge distribution obeys the following rule p r Ar R R G Find a Spts The value of the constant A b 5pts The electric field as a function of distance from the center of the conducting sphere c 5pts Consider a point like particle of charge q mass m located at a distance Rj R from the center of the sphere If the particle is moving with initial velocity vo directed that will allow the

If charge on a body is 2 nC then how many electrons are absent from the body 1 5 1027 1 25 1028 1 25 1010 1019

Four charges q q q q are placed on circumference of a circle of radius R as shown in the figure What is electrostatic force on qo placed at the centre of the circle q q qo 990 2 2R 80 8990 4 ER 2990 4 ER q