Electric Field and Potential Questions and Answers

An insulated conductor initially free from charge is charged by repeated contacts with a plate which after each contact is replenished to a charge Q from an electrophorus If q is the charge on the conductor after the first operation prove that the maximum charge which can be given to the conductor in this way is Qq Q q

14 A particle of mass 2 kg and negatively charged is released form very large distance along the tunnel diametrically of uniformly positively charged spherical distribution as shown in figure it the speed at mouth of tunnel is 2 m s then find KE in Joule at centre Assume gravity free space

2 If the potential energy of the system is 50 J then the work done in taking charges 2 and 23 from infinity to given positions is a greater than 50J b 50 I c less than 50J d None 92 21 61 83 82 93

A Circular ring of radius 3a is uniformly charged with charge q is kept in x y plane with center at origin A particle of charge q and mass m is projected from x 4a towards origin Find the minimum speed of projection such that it reaches origin X X q 3a X X 4a q

An electric dipole is placed at the centre of a sphere Which of the following is correct 1 The electric flux through the sphere is zero 2 The electric field is zero at every point on the sphere 3 The electric field is zero at every point inside the sphere 4 The electric field is uniform inside the sphere

Two positrons e and two protons p are kept on four corners of a square of side a as shown in figure The mass of proton is much larger than the mass of positron Let q denotes the charge on the proton as well as the positron then the kinetic energies of one of the positrons and one of the protons respectively after a very long time will be A 4x a 22 4 5 22 a B 2 a 4 2x 2 to

Q6 Two like charges 5cm apart are repel each other with a force of 4 2 10 3N If one charge is 100 C what will be the other

hollow conducting 21 Consider an initially neutr spherical shell with inner radius r and outer radius 2r A point charge Q is now placed inside the shell at a distance r 2 from the centre The shell is then grounded by connecting the outer surface to the earth P is an external point at a distance 2r from the point charge Q on the line passing through the centre and the point charge Q as shown in the figure 21 2 Q 2r P The magnitude of the force on a test charge q placed at P will be

A dipole with a dipole moment of magnitude p is in stable equilibrium in an electrostatic field of magnitude E Find the work done in rotating this dipole to its position of unstable equilibrium All India 2010C

The coefficient of mutual inductance of two coils is 5 H The current through the primary coil is 4 0 5 A reduced to zero value from 3 A in 1 millisecond The induced e m f in the secondary coil will be A02 3 15 KV 1 30 KV 2 1 67KV 4 600 V

A metal sphere A of radius r charged to a poterlal is enveloped by a thin walled conducting spherical shell B of radius r Then potential 2 of the sphere A after it is connected to the shell B by a thin conducting wire will be 1 5 1 2 8 1 12 3 d m XX 1 it B 2 4 51 41

A metallic shell has a point charge q kept inside its cavity Which one of the following diagrams correctly represents the electric lines of forces 1 3 2 4

17 A point charge q of mass m is placed at the centre of a fixed ring of charge Q and radius R What minimum velocity along the axis of ring should be give to q so that it would reach far away from ring if i q is positive ii q is negative 5x64 Ring

Five Styrofoam balls are suspended from insulating threads Several experiments are performed on the balls and the following observations are made i Ball A repels C and attracts B ii Ball D attracts B and has no effect on E iii A negatively charged rod attracts both A and E An electrically neutral Styrofoam ball gets attracted if placed nearby a charged body due to induced charge What are the charges if any on each ball A B C D and E Choose only 1 answer A B 0 O Your Answer

A capacitor made of two circular plates each of radius 12 cm and separated by 5 mm The capacitor is being charged by an external source The charging current is constant and equal to 0 15 A The capacitance of the parallel plate capacitor is 0 O o a 40 pF b 45 pF c 70 pF d 80 pF 8 In the question number 7 the rate of change of potential difference between the plates is

Consider a uniform charged sphere of charge density p and radius R If the cavity of radius 0 5R is made inside the sphere and the removed part is again placed near the charge distribution as shown in the figure The electric field at the centre of the cavity is times pR 280

Figures shows some equipotential lined distributed in space A charged object i moved from point A to point B 20V 40V 10v 20v 30V 40V 50V 30V B 10v 30V 50 10 20 40 50

Ques 14 INTEGER It requires 1 mJ of work to move two identical positive charge q from infinity so that they are separated by distance a How much work in mJ is required to move four identical positive charges q from infinity so that they are arranged at the vertices of a tetrahedron with edge length a 1 4 Click here to answer 2 5 Marks 4 3 6 X Don

Consider two hollow concentric spheres S and S enclosing charges 2Q and 4Q respectively as shown in the figure i Find out the ratio of the electric flux through them ii How will the electric flux through the spheres S change if a medium of dielectric constant is introduced in the space inside S in place of air Deduce the necessary expression All India 2014 4Q 2Q S S2

Electric field in a region is given as E 10 5x i A charge particle of mass 5kg and charge Q IC is situated at origin and free to move in given electric field Then choose the correct options Neglect gravity A Motion of charge particle is Oscillatory B Maximum displacement of charge particle from origin is 4 SI units C Maximum velocity gain by charge particle is 2 SI units D The position of charge particle when velocity gained by particle is maximum is 2 SI units

If two electrons are each 1 5 10 m from a proton as shown in Figure magnitu the net electric force they will exert on the proton is 65 0 P Oe a 1 97x10 8N b 2 73x10 8N c 3 83x10 8N d 4 63x10 8N

A charge is uniformly distributed in a spherical volume o radius R The electric field at distance r r R from its centre is proportional to r 1 r 2

2 Two charges of magnitudes 2Q and Q are located at points a 0 and 4a 0 respectively What is the electric flux due to these charges through a sphere of radius 3a with its centre at the origin All India 2013

ENGLISH Q No 2 Single Correct A A Marks 4 00 1 C If 91 92 8q then which of the following force between 9 and 92 is not possible for a given distance r A B q Teor 2q Eor C 8q Eor

An electron and a proton are at a distance of 14 Angstrom Th dipole moment of this system will be 2 48 x 10 16 Cm 2 48 x 1028 Cm 1 x 10 2 Cm 2 24 x 10 28 C m

Problem Three charges are situated at the corners of a square side a as shown in Figure How much work does it take to bring in another charge q from far away and place it in the fourth corner How much work does it take to assemble the whole configuration of four charges q a

Figure shows electric field lines due to two charges 9 and 92 The signs and magnitude of two charges are 9 92 Both are negative and 19 1 1921 Both are positive and magnitude of q greater than magnitude of 92 Both are negative and magnitude of 92 greater than magnitude of 9 92 is positive and q is negative

Two connected charges of q and q respectively are at a fixed distance AB apart in a no uniform electric field whose lines of force are shown in the figure The resultant effect on the two charges is B q

To 5 In the arrangement of two concentric conducting shell as shown in the figure charge on the outer shell is 10 C and the inner shell is grounded Ther the charge q on the inner shell is f S 1m 10 C 2m owT i od S of 1 Zeroo is yenT nw 2 q 10 C 00

A charge q 10 6 C of mass 2 g fig is free to move when released at a distance a from the fixed charge Q Calculate its speed when it recedes to a distance b Assume a 1 m b 10 m Q 10 C A B C 90 m s 9 m s 900 m s fixed none of these Qaq b My Answer

Variation in potential is maximum if one goes 1 Along the line of force 2 Perpendicular to the line of force 3 In any direction 4 None of these In moving from A to B along an electric field line

Two molecule each with permanent dipole moment p are aligned as shown Calculate the force between the molecules if they are separated by a distance that is large compared with the dimension of the dipoles Hint The relation 1 x 1 2x 3x for small x is useful p p 126

Which of the following graphs most appropriately gives variation of magnitude of electric field due to an infinitely long thin uniformly charged cylindrical shell of radius R with distance r from its axis

Two identical spherical conducting bodies A and B carries charges 2C and 8C respectively Now a 4C charge is added to both of them and then they are made in contact for some time Then they are separated The number of electrons present in excess or deficient in them are A 2 5 x 10 6 in excess C 6 25 x 10 8 in deficient E 3 75 x 10 8 in excess othese B 2 5 x 10 6 in deficient 16 D 6 25 x 10 8 in excess

Two conducting spheres of radii R and R are charged with charges Q and Q respectively On bringing them in contact there is SIR A no change in the energy of the system B an increase in the energy of the system if Q R Q R C always a decrease in energy of the system D a decrease in energy of the system if Q R Q R

If q q2 8q then which of the following force between q and q2 is not possible for a given distance r B q or 2q TEOR 8q Teor q 2mor

Inside a neutral conductor sample of arbitrary non spherical shape a non spherical cavity is present There is a point charge inside the cavity The induced surface charge density on the inner surface of cavity and outer surface of the conductor respectively is Uniform and non uniform Non uniform and uniform Non uniform on both surfaces Uniform on both surfaces

Charges q q and q coulomb are placed at the points i j k i j k and i 1 k respectively The x component of electric field at the origin will be 1 1 q 4TE 3 3 1 3 4 E q allm 1 2q 2 4 3 3 4 None of these

SolveLancer Test Consider that at any time t 0 a small particle of mass 2 x 10 5 kg comes in the influence of An electric field given by E t Eo sin wt Charge on particle is 3 0C and Eg 6 Consider only influence of the electric field the maximum speed attained by particle is Given w 1 x 10 rad s SolveLancer Test a 2 m s b 90 m s c 45 m s d 28 5 m s

29 In a certain region of space electric field is along the z direction throughout The magnitude of electric field is however not constant but increases uniformly along positive z direction at the rate of 106 N Cm The force experienced by a dipole of dipole moment 0 2 x 10 5 Cm in negative z direction is 1 2 N along z direction 30 2 2 N along z direction 3 ON 4 2 N along x direction

7 Find ratio of electric field at point A and B Infinitely long uniformly charged wire with linear charge density is kept along z axis ZA A 3 4 6 X I B 3 4 0

Q de 0 RCose Rde RSine r RCose P dear teacher listen to my question prop erly Find the electric field at point P1 using elemental integration Plz do n t use gaws law use only by elemental integration Look my question prope rly

Electric field intensity at a point varies with distance as for OA point charge O An infinite line of charge O A plane infinite sheet of charge O An electric dipole at equatorial position

A charge Q is kept at the corner of a cube Electric flux passing through one of those faces not touching that charge is 1 Q 24 2 0 3 3 8 6

Two charges q1 and q2 are kept on x axis and electric field at different points on x axis is plotted against x Choose correct statement about nature and magnitude of q1 and 92 4 O q ve q2 ve 191 192 O q1 ve q2 ve 1911 19 Oq1 ve 92 ve 91 92 92 O 91 ve 92 ve 9 Marks 4 1

4kq 3 zero Two point charge q and 4q are placed at a 0 and 4a 0 respectively Then position of neutral point will be 1 x a 2 x 0 3 x 2a 4 x a Two identical balls each having a density p are 7

in a certain conservative force field has a potential 20xy Z The force exerted on it is energy given by V 1 20V 20x i 20x 25 20V i 20x i 20x Z 20v i 20x i 20x k 20x1 x 20xy 27 fareil fafeeff V Z Class XI Marcel Batch WPE 1 20Y i 20x i 20xy j k z 20V i 20x 20 k Z 3 4 20y i 20x i 20 ix 4 20Y i 20x 20 20v i 20x i 2017 k Consider a one dimensional motion of a particle with total 28 Each o GRI

0 Four changes are arranged at the corners of a square ABCD as shown in the adjoining figure The force on a positive charge kept at the centre O is D 2q 24 2q B C 1 Zero 2 Along the diagonal AC 3 Along the diagonal BD 4 Perpendicular to side AD Two small spherical balls each carrying a 12 Ach surf If ra dr dt 1

Which electric field is responsible for the proton s trajectory as shown below Parabolic trajectory

Courses Physics Electric Field and Potential Question 1 A charged particle of mass m and charge e has velocity u when at a d istance d from a conducting plate crosses it at point B The length of the plates AB s l Then the charge density of the pla id charge e has