Electric Field and Potential Questions and Answers

The car makes a displacement of 100 m towards east and then 200 m towards north The magnitude and direction of the resultant are respectively 1 223 7m tan 2 N of E 2 223 7m tan 2 E of N 3 300m tan 2 N of E 4 100m tan 2 N of E

C zero A charge q is distributed uniformly on a ring of radius a A sphere of equal radius a is constructed with its centre at the periphery of the ring Calculate the flux of the electric field through the surface of the sphere 9 A 380 q C 480 B 2q 380 3q D 480

There is a uniform electric field of magnitude 4 N C whose Z component is zero and which makes an angle 30 with the X direction The work done in slowly taking a positive charge of magnitude 1 C from the point 0 2 to the point 0 2 along a circular path centred at the origin is J xm 4 0 2 0 2 y m 300 Jay

In the given electric field E d x i E N C a hypothetical closed surface is taken as shown in figure The total charge enclosed within the closed surface is Ke Then find the value of k a 2m b 3m and c 2m E E j N 0 0 0 Ed x i

At the four corners of a square of side 1 m four identical charges each 10C are placed The electric potential energy of the system is 1 360 J 2 180J 3 180 2 4 360 2J

3 Two positive charges q and q are placed at the diagonally opposite corners of a square and two negative charges q and 9 are placed at the other two corners of the square Then at the cen tre of the square the resultant electric intensity and the net electric potential V are 1 E Q V 0 2 E 0 V 0 3 F 01 0 V

Q 24 A charged dust particle of radius 5 x 107 mis located in a horizontal electric field having an intensity of 6 28 x 10 V m The surrounding medium is air with coefficient of viscosity n 1 6 x 10 5 N s m If the particle moves with a uniform horizontal speed 0 02 m s the number of electrons on it is

conducta Charge off is separated by holding a positively charged rod very closely near by as shown in fig Assume that the induced negative charge on the conductor is equal to the positive charge q on the rod Then flux through surface is A zero C q 80 Conductor D B q E D

c Flux depends on symmetry d Not sufficient information Charges can neither be created nor destroyed it can be transferred from one place to another The force between two charges are given by coulomb s law To find the force acting on a unit positive test charge electric field is calculated due to that charge The electric field always originates from ve charge and ends on ve charge Electromagnetic waves can be generated that transported energy Q6 Does Coulomb s law agree with Newton s 3rd law a No c May be Q7 What is the inherent characteristic of matter a Charge is inherent characteristic c Coulomb s law is not applicable in vacuum b Yes d Can t say Q9 Can Coulomb s law be used to define unit of charge a Yes c May be b Quantization of charges d None of the above Q8 Are electric field E and force F vector or scalar quantity a E is vector quantity and F is scalar c E is scalar F is vector b E and F are vector quantity d E and F is scalar b No d Can t comment Q10 Is physical significance of EM field useful in electrostatics a Yes c May be b No d Not sufficient information

E at one face parallelepiped is uniform over the entire face and is directed out of the face At the opposite face the electric field E is also uniform over the entire face and is directed into that face The two faces in question are inclined at 30 from the horizontal while E and E both horizontal have magnitudes of 2 50 x 10 N C and 7 00 x 10 N C Assuming that no other electric field lines cross the surfaces of the parallelepiped determine the net charge contained within 5 00 cm K A 67 5 C 6 00 cm FI 300 B 37 5 C

70 Three charges Q and q and tq the vertices of right angled isosceles trianlge as shown in the figure The net electrostatic energy of the configuration is zero if Q is equal to 1 9 1 2 3 2q Fra 9 2 29 1 2 4 q

Zero Marks 0 In all other cases The electric potential V in volt in a region of space is given by V ax ay 2az2 where a is a constant given by a 1 25 x 103 V m What is the radius in m of the circle of the equ line corresponding to V 6250 V and 2 V 2m

2 A hemispherical surface of radius R is placed uniform electric field E as shown in Fig Flux with its cross section perpendicular to a linked with its curved surface is A zero C TR E E R B 2 R E 1 D TR E 2 TR

Q7 What is the inherent characteristic of matter a Charge is inherent characteristic c Coulomb s law is not applicable in vacuum b Quantization of charges d None of the above Q8 Are electric field E and force F vector or scalar quantity a E is vector quantity and F is scalar b E and Fare vector quantity

following statement is are TRUE Assume steady state 10V SRAM C C C 5 F which of the B Ca R 1 10V ATHE A Potential of point O can be determined but that of B can t be determined B Potential of both point O B can t be determined C If charge on capacitor C were also specified potential of point O can be determined but that of B can t be determined D If charge on capacitor C were also specified potential of both the point O B can be determined

Two charges 5uC and 4 C are seperated by a distance 20cm in air Work to be done to decrease the distance to 10 cm is 1 1 8J 2 0 45J 3 2 7J 4 0 9 J the corners of an equilateral triangle of side

Four identical charges each of charge q are placed at the corners of a square Then at the centre of the square the resultant electric E and the net electric potential V are 1 E QV 0 3 E 0 V 0 63 T intensity 2 E 0 V 0 4 E 0 V 0

View In English Shown in the figure is a spherical shell with inner radius a and outer radius b which is made of conducting material A point charge Q is placed at the centre of the shell and a total charge c placed on the shell Charge is distributed on the surfaces as 2 3 orrect Answer 2 ur Answer 3 Q on the inner surface q on the outer surface Q on the inner surface q Q on the outer surface Q on the inner surface q Q on the outer surface The charge q is spread uniformly between the inner and outer surfaces

CLO 2 Figure below shows a section of three long charged cylinders centered on the same axis Central cylinder A has a uniform charge QA 390 900 What uniform charges qs and qc should be on cylinders B and C so that if possible the net electric field is zero at point 1 98 9c 390 98 390 9c 0 C 98 0 9c 390 Electric field can not be zero at point 1

22 An electric dipole is situated in an electric field 22 of uniform intensity E whose dipole moment is p and moment of inertia is L If the dipole is displaced slightly from the equilibrium position then the angular frequency of its oscillations is 1 PE 1 2 1 2 2 PE 4 31 2 1 2 yen farge faya formen Ifaga en taita safarit 1 3 1 2 en Entfe faga a fercenfura a fear and a sud de 9 2 PE 3 2 4 P

A particle having a mass of 10 2 kg carries a charge of 5 x 10 8 C The particle is given an initial horizontal velocity of 105 m s 1 in the presence of electric field and magnetic field B To keep the particle moving in a horizontal direction it is necessary that 1 should be perpendicular to the direction of velocity and should be along the direction of velocity 2 Both Band E should be along the direction of velocity 3 Both Band E are mutually perpendicular and perpendicular to the direction of velocity 4 B should be along the direction of velocity and should be perpendicular to the direction of velocity Which one of the following pairs of statements is possible Mains 201011

The region of a non conducting sphere rdenotes the distance from the centre of the sphere is uncharged and the regionsr is charged with charge density p r po where po is a constant In the regionsrs R the electric field E r varies as O E r O Po 48 R O Eir 0 Eir Po R 167

2 1000 small water drops each of radius r and change q coalesce to form one spherical drop The potential of big drop is larger than that of smaller ones by a factor 0 2 100 3 10 4 1

Three charged particle A B and C with charges 4q 2q and 2q are present on the circumference of a circle of radius d the charged particles A C and centre O of the circle formed an equilateral triangle as shown in figure Electric field at O along x direction is 1 3 2q B 2 3q d 3 39 4d 50 d 30 d A 30 C 2q 9 39 46d 39 Ed

An infinite length of cylinder of radius R has uniform charge density p then choose the correct option s rradial distance from central axis of cylinder Electric field at distance r r R is proportional to r Electric field at distance r r R is proportional to r Electric field inside the cylinder is constant Flectric field outside the cylinder is constant

1 A charge of 6 25uC in an electric field is acted upon by a force 2 5N The potential gradient at this point is 1 4 10 V m 3 2 5 10 V m 2 4x10 V m 4 none ont

Tvo thin conducting spherical shells of radii Rand 3R are fixed concentrically and given total charge Q and Q respectively Which of these options is are correct 0 The electric field at a point at a distance 2R from the their common centre has magnitude The electric field inside the inner shell is zero Q 6x R The potential at their common centre is The potential of the outer shell is zero e 16R and is directed radially inward

Asseetion A The kinetic energy of a charged particle moving in a uniform Magnetic field does not change Reason R In a uniform magnetic field no force acts on the charged particle A a B b C C D d

A charge q is placed at the centre of the open end of a cylindrical vessel The flux of electric field through the surface of th vessel is A zero B 9 C 2 Eo 2q 0 doctric field in a region is given by 9 D

3 4 10 28 Charges 20 30 40 and 50 C are at the corners of a square of 10 cm The field at the point of intersection of the diagonals is 1 360 10 10 N 2 360 10 3 360 10 C N C N C

1 4E 4 48 Two point charges q and 9 2 are situa the origin and at the point a 0 0 respecti The point along the x axis where the electric vanishes is a 1 X 2a 3 x 2 1 2 x 2a 2a 4 2 1 icts betw

Two thin conducting spherical shells of radii R and 3R are fixed concentrically and given total charge Q and Q respectively Which of the options is are correct The electric field at a point at a distance 2R from the their common centre has magnitude O The electric field inside the inner shell is zero Q 67 R O The potential at their common centre is O The potential of the outer shell is zero Q 16R and is directed radially inward

3 450NC An electron is projected into an elect intensity 9x10 NC in the direction of the field acting towards east Its acceleration is 1 1 6 10 8 ms 2 towards west 2 1 6 10 8 ms 2 towards east 3 9 10 ms 2 towards west 4 9x19 8 ms 2 towards east are seperated

Infinity the electric field between the plates of a cathode oscilloscope be 1 2x10 N C the deflection that an electron will experience if it enters at right angles to the field with kinetic energy 2000 eV is The deflection assembly is 1 5cm long 2 3 4 cm 1 0 34 cm 4 0 34 mm 0034 mm 90 160 are placed 10

ses m and 1 Two ch have charges 3q and q respectively are kept in a uniform electric field and alle to move for the same time The ratio of kinetic energies is 1 1 9 2 1 27 4 37

Two identical tiny metal balls carry charges of E nC and 12nC They are 3cm apart The balls are now touched together and then separated to cm The force on them is 20 25 10 N 2025 10 N 2 2 025 10 N 4 2025N A spheres are suspended by

33 Two point charges of magnitude 4 C 9 C are 0 5m apart The electric intens zero at a distance x m from A and y m B x and y are respectively 4MC P 1 0 5m 1 0m 2 1 0m 1 5m 3 A 0 5m 0 5m 9MC 100 B

29 The vertices of an equilateral triangle lie on the circumference of a circle of radius 6 cm Charges each of 3C are placed at the vertices If a charge of IC is placed at the centre of the circle the force acting on it is 1 0 75 10 N 3 2 25x10 N 2 1 5 10 N 17

d None of these Two small balls A and B are launched in the same vertical plane simultaneously with same speed of 20 m s at t 0 Ball A has an initial horizontal velocity and ball B has initial velocity at an angle 0 above 100 m the line joining A and B as shown If the projectiles collide in mid air at time t then a 0 30 c t 20 3 b 0 60 10 d t 3 20m s 100 3 m 20m s B

4 The point charges 1C 1C and 1C are placed at the vertices A B and C of an equilateral triangle of side 1m Then A The force acting on the charge at A is 9 10 N B The electric field strength at A is 9x10 NC 1 A is correct but B is wrong 2 B is correct but A is wrong 3 Both A and B are wrong 4 Both A and B are correct

charges Q 4Q 9Q are placed at distances of 1 2 3 metres from a point O on the same straight line Then field at O is 1 Zero 2 47 Q 3 Zero or 47 respectively odd We cannot say according as n is even or

Q 16 54 Two thin circular rings A and B both of radius R are fixed coaxially with a distance FR between their centres and charged uniformly with total charge Q and Q respectively A particle of mass m carrying charge q is released from the centre of the ring A If the particle reaches the centre of ring B with velocity X 12 Qg 4x Rm

small conducting spheres each of mass kg kg are suspended from the same point In conducting strings of length 100 cm They en equal and similar charges until the strings ually inclined at 45 each to the vertical

4 attractive force 24F Three charges each equal to 10 C are placed at the corners of equllateral triangle of side Im The force on one of the charges is 1 9 10 N 2 9 3x10 N 3 27 10 N 4 18 10 N 6 and 6C attract each

3 27x10 N Two point charges of 2C and 6C attract each other with a force of 12N A negative charge of 2C is added to 6C charge now the force between them is 1 12N 3 32N 2 16N 4 24N and carrying

Two identical charges are placed at two corners of an equilateral triangle The potential energy of system is U The work done in bringing an identical charge from infinity to third vertex is OU 2U 3U

11 The excess equal in number in number of electons that must be placed on each of two small spheres spaced 3 cm apart with force of repulsion between the spheres to be 10 19 N is 1 25 2 225 3 625 4 1250 a and A tiala of charge mass m

case with or without selection of any correct option s will result in 2 marks A solid metal sphere has a charge 3Q and radius is a which is concentric with conducting spherical shell of radius b having charge Q Choose the correct statement s 1 3Q 4TTEO R Electric field at distance R a R b is Electric field at distance R R b is Electric potential at R a R b is Electric potential at R R b is 1 4TEO 1 4TEO 1 4 EO 2Q R2 3Q R 2Q R In this case will result in 1 marks Selecting ar

Two small spherical shells have charges 9 C and 6 C separated by a distance r experience a force F When a charge of 3 C is given to each sphere and kept at same distance as before The new force of repulsion becomes NITI O2F O 3F

A thin fixed ring of radius 1 meter has a positive charge 1 x 105 coulomb uniformly distributed over it A particle of mass 0 9 g and having a negative charge of 1 x 10 coulomb is placed on the axis at a distance of 1 cm from the centre of the ring Show that the motion of the negatively charged particle is T approximately simple harmonic The time period of oscillations is Find k k