Electric Field and Potential Questions and Answers

9 45 10 cm Mark for Review The dipole moment of the configuration shown in the figure is 1 0 C 2 0 C 10 cm 10 cm 3x10 7 C m 2 107 Cm 3 107 Cm 3 0 C 01 26 hr min 7 107 Cm

3 Both 1 2 4 Neither 1 nor 2 The distance between the plates of a parallel plate capacitor is 3 mm and the potential difference applied is 3 x 105 V If an electron travels from one plate to another the change in its potential energy is 1 3 x 105 eV 3 108 eV 2 900 eV 4 Negligible Now Delhi 110005 Ph 011 476234

A solid sphere of radius R has a charge Q distributed in its volume with a charge density p kra where k and a are constants and ris the distance from its centre If the electric field at R 1 IS times that at r R find the value of a 2 o

Please solve this query A point charge q is kept on equatorial position of an electric dipole of dipole moment p at distance r as shown in the figure Electric potential at the centre of dipole is 9 P P 4 er x Zero a

Two mutually perpendicular infinite wires along x axis and y axis carry charge densities and 2 The electric line of force at P is along the line y x 3 Where P is also a point lying on the same line Find the 2 2 8 P 24 X 00 E

A 0 70 m radius cylindrical region contains a uniform electric field that is parallel to the axis and is increasing at the rate 5 0 x 1012 V ms The magnetic field at a point 1 2 m from the axis has a magnitude of a neq eviisler nedt 0 1 O 3 1 1 10 5 T X 2 7 0 10 T 4 2 3 10 5T S

Two insulated charged metallic spheres A and B have their centres separated by a distance of 50 cm in air a calculate the force of repulsion between them if the charge on each is 5 0x108c b calculate the force of repulsion between them when the two spheres are placed in water dielectric constant of water is 81 0 MEDT

3 Vertical and down 10 Two charges 4q and q are kept at a 0 and a 0 respectively The graph showing the variation of electric field along x axis is x a St x a 4 X a the plantric field on vaxis will be maximum at y x a x a

Question Number 46 Question Id 9046847150 Question Type MCQ Option Shuffling Yes Is Question Mandatory No Correct Marks 1 Wrong Marks 0 A point charge of 625 nC is placed in an x y plane at point 2 m 0 m Let i and j be the unit vectors along the x axis and y axis respectively Then the electric field at a point 0 1 5 m in vector notation is take 1 40 9 10 Nm C Options 90468423824 18N C i 12N C j 90468423825 24N C i 18N C j 90468423826 36N C i 27N C j 90468423827 72N C i 54N C j 1691703s Quention Type MCQ Option Shuffling Yes Is Question Mandatory No

8 A non uniform but spherically symmetric distribution of charge has a charge density p r given by p r po 1 r R for r R 0 for r R where po is a positive constant i Find the value of the total charge contained in the charge distribution ii Obtain an expression for the electric field in the region r R

R 20 For the given R L circuits the current through the cell just after switch is closed 1 E 18R M 65 3R ww 6R ww S 3R ww The current through cell at t 0 is 10E 18R E emf 3R ww ooooooo L 2 2E N

A bead of mass m and charge q is threaded on a smooth wire kept along x axis A second charge Q is fixed at the point x 0 y d It is projected with high speed so that it is initially near x and it ends up near x 00 As the moving charge passes the stationary charge find the impulse exerted by the wire on the bead Neglect gravity and assume the speed to be constant A B qQ 2 vd qQ 4 vd C qQ Evd D 2qQ Evd

26 1 unit ST ii A small metal sphere carrying charge Q is located at the centre of a spherical cavity inside a large uncharged metallic spherical shell as shown in the figure Use Gauss law to find the expressions for the electric field at points P and P iii Draw the pattern of electric field lines in this arrangement Delhi 201261

Two point charges place IC and 0 0 are 10cm apart in vacuum Calculated the mag nitude of electric field intensity at the middle point of the line joining the charges and mention its

distance r from a long thread charged uniformly with linear charge density X Force Facting on the dipole if vector p is oriented along the thread is zero Force Facting on the dipole if vector p is oriented along the radius vector is F 1 p 28 Force Facting on the dipole if vector p is oriented at right angles to the thread and radius vector 7 is F p 201 By all means if the dipole is left on its own in the vicinity of the thread then distance of

i Define electric flux Write its SI unit ii A uniform electric field for x 0 and E E N C E E i N C for x 0 are given A right circular cylinder of length cm and radius r cm has its centre at the origin and its axis along the X axis Find out the net outward flux Using the Gauss law write the expression for the net charge

Ants can become charged and can be treated as point charges Two ants are resting on a string The first ant is resting at x 6 0 m and has charge q 7 2 C The second ant is resting at x 4 0 m and has charge q2 4 5 C Between the two ants at what location along the x axis is the total electric field zero m

Two identical conducting spheres are charged by induction and then separated by a large distance sphere 1 has charge Q and sphere 2 has charge Q A third sphere is initially uncharged If sphere 3 is touched to sphere 1 and separated and then touched to sphere 2 and separated what is the final charge on each of the three spheres

A non conducting ring is of radius 0 5 m 1 11 x 10 10 coulombs charge is non uniformly distributed over the circumference of ring which produces electric field E around itself If 0 is the centre of the ring then the value of l 0 S E de is l 0 1 2 V 2 2 V 3 1 V 4 zero

Three infinitely long charged thin wires are placed along x y z axes Their line charge densities are X 2 and 3 respectively Then You Missed AE at point a a 0 is X independent of 2 B C D Ez at point a a 0 is proportional to X X 20 E at point a a 0 is proportional to X X 12 E in z direction at point a a 0 is

3 An electron and proton are placed in an electric field The forces acting on them are 50 4 a a and F and their accelerations are a 1 F F 2 F F 0 and a respectively then 3 a a

8 AB and CD are two uniform resistance wires of lengths 100 cm and 80 cm respectively The connections are shown in the figure The cell of emf 5 V is ideal while the other cell of emf E has internal resistance 2 52 A length of 20 cm of wire CD is balanced by 40 cm of wire AB Find the emf E in volt if the reading of the ideal ammeter is 2 A The other connecting wires have negligible resistance MO 5 V AL Cr E HH 40 cm 20 cm ww 292 1 B D Ammeter ideal

A solid conducting sphere of radius R 0 2 m is charged with a charge Q The magnitude of the electric potential at point A a distance r 6 m from the center is VA 2000 What is the electric potential in kV at point s on the surface of the sphere R 0 2 m 90 24 30 15 60 18 r 6m A

On a fixed frictionless non conducting rod bent at right angle can slide two beads of equal mass m carrying charges q and q of opposite signs Initially the beads are held at rest at 92 distances d and 2d from the corner as shown Now they are simultaneously released When one of the beads reaches the corner where would the other bead be located Treat the beads a particles

If charge q is fixed and q is free to move then find out the velocity of q when it reaches distance r after it is release from a distance of r from q as shown in figure Assume friction is absent 94 fixed 92 r2 Find v of q when it reaches distance r after it is released from rest

Two spherical conductors A and B of radii R and 2R respectively are each given a charge Q When they are connected by a metallic wire The charge will O flow from A to B O flow from B to A O O remain stationary on conductor none of these

placed at the vertices of a square of side a 1 4 m If q 18 nC q 24 nC q3 35 nC and q 16 nC then find the electric potential at the centre P of the square Assume the potential to be zero at infinity The distance of the point P from each charge is a 2 1 4m 1 4 V V V V V 1 4 1m 4TLE 91 92 93 94 12 13 14 1 9 92 93 94 r 949 93 H P 9 0 92 1 41E0 9 109 45 10 V 405 V 18 24 35 16 10 C 1m

In the circuit shown in the figure the A C source gives a voltage V 20 cos 2000 t volt neglecting source resistance the voltmeter and ammeter readings will be 60 5 mH 40 00000 V 1 OV 1 4A 2 5 6V 1 4A 3 OV 0 47 A 4 1 68 V 047 A A 50 F HH

4 Decreases as r increases r R Two parallel infinite line charges with linear charge 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 GINEET 2019 1 Zero 2 3 4 22 TE R TER N C N C 2TE R N C x m denize By gruess law TLU F q 6 distance directed field is n same A through fall of th of the p 1 Sn 2 5 3 E 4 7 Sup diffe

The electric potential in volts due to an electric dipole of dipole moment 2 10 cm at a distance 3m on a line making an angle of 60 with the axis of the dipole is 1 zero 2 10 3 20 3 40

BOOKS 21 An electric dipole is placed along the x axis at the origin O A point P is at a distance of 20 cm from this origin such that OP makes an angle T with the x axis If the 3 electric field at P makes an angle value of 0 would be a c 7 3 2 3 b T 3 with the x axis the MP PMT 1997 tan d tan 1 3 2 3 2

In a region of space suppose there exists a uniform electric field E 101 Vm If a positive charge moves with a velocity 2j its potential energy at this moment V 1 Increases 2 Decreases 3 Does not change 4 Both 1 and 2

Six point charges are placed at the vertices of a regular hexagon of side a as shown If E represents electric field and V represents electric potential at O then q O Ta1 1 E 0 but V 0 3 E 0 and V 0 q 2 E 0 but V 0 4 E 0 and V 0

There exists a uniform electric field E 4 x 105 Vm 1 directed along negative x axis such that electric potential at origin is zero A charge of 200 C is placed at origin and a charge of 200 uC is placed at 3 m 0 The electrostatic potential energy of the system is 1 120 J 3 240 J 2 120 J 4 Zero

n isolated conducting sphere has a 13 cm radius One wire carries a current of 1 0000049 A into it while another wire arries a current of 1 0000000 A out of it How long in seconds would it take for the sphere to increase in potential by 80 V

5 29 A triangular wire frame having each side equal to 2m is placed in a region of time varying magnetic field having dB dt 3 T s The magnetic field is perpendicular to the plane of the triangle as shown in figure 5 293 The base of the triangle AB has a resistance 12 while the other two sides have resistance 252 each The magnitude of potential difference between the points A and B will be A 0 4V C 1 2V X A X Cx Go Figure 5 293 B B 0 6V D None 24860 25mm 60 A C 5 3 giv the

Two particles of masses m and 2m with charges 2q and q are place in a uniform electric field E and allowed to move for same time Find the ratio of their kinetic energies A B 8 1 4 1 2 1 Your Answer

8 Two similar spheres when placed 2 cm apart attract each other with a force of 4 dynes The spheres are connected by a wire On removing the wire the spheres now repel each other with a force of 2 25 dynes Calculate the initial charges on the sphere neglecting the capacity of the wire

Assertion The change in potential energy of a two charge system is independent of the choice of zero potential energy reference Reason Potential energy of a charge may decreases when it moves opposite to electric field A B C Both Assertion and Reason are true and the Reason is the correct explanation of the Assertion Both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion Assertion is true but the Reason is false

3 14 A ring of charge with radius 0 5 m has 0 002 m gap If the ring carries a charge of 1 C the electric field at the center is a 7 5 x 107 NC 1 b 7 2 x 107 NC 1 c 6 2 x 107 NC 1 d 6 5 x 107 NC x x Fig 1 143

1 1 5 2 1 1 3 How far apart should the 2 electrons be if the force each exerts on the other is equal to the we the electron m 9 1 x 10 31 kg e 1 5 08 cm 2 5 08 m 3 2 54 m 4 254 m hown in figur

Two point charges q and q2 of 2 10 C and 2 x 10 C respectively are placed 0 4 m apart Calculate the electric field at the centre of the line joining the two charges CBSE F 94C

Semivertex of the conical surface obtained by taking dipole moment as axis on which electric field by dipole becomes normal to moment of th dipole is equal to 1 tan 2 3 tan 3 2 tan 2 4 tan 3

on 4 A steel wire of 4 0 m in length is stretched through 2 0 mm The cross sectional area of the wire is 2 0 mm If Young s modulus of steel is 2 0 x 10 N m find a the energy density of wire b the elastic potential energy stored in the wire Here 4 0 m

Four metallic plates are placed as shown in the figure Plate 2 is given a charge Q whereas all other plates are uncharged Plates 1 and 4 are joined together The area of each plate is same SKAL d 2d 97 The charge appearing on the right side of plate 3 is A 0 B Q 4 3 Od C 3Q 4 98 The charge appearing on right side of plate 4 is A 0 B Q 4 99 The potential difference between plates 1 and 2 is Qd C 3Q 4 C 3 Qd D Q 2 D Q 2 3Qd D A

A solid conducting sphere having a charge surrounded by an uncharged concentric conducting spherical shell Let the potential difference between the surface of the solid sphere and the outer surface of the shell be V If the shell is now given a charge 3Q the new potential difference between the same two surfaces is 1 V 3 4V 4 2V 2 2V ATICS02 EXERCISE P65

34 Find the currents in different resistors shown in figure 89 www 292 www 20240 J 2 VT 2 V 2 V 892

If an electric dipole is placed in an electric field generated by a point charge then 1 1 the net electric force on the dipole must be zero 2 the net electric force on the dipole may be zero 3 the torque on the dipole due to the field must be zero 4 the torque on the dipole due to the field may be zero

A proton and an a particle enter a uniform magnetic field perpendicular with the same speed If proton takes 20 us to make 5 revolutions then the periodic time for the a particle would be 1 5 s 2 8 s

will not experience a et force Two charged particles are placed at a distance 1 0 cm apart What is the minimum possible magnitude of the electric force acting on each charge 100 LI