Electric Field and Potential Questions and Answers

An infinite large non conducting plane of surface charge density o has circular aperture of certain radius curved out from it The electric field at a point which is at a distance a from centre of G aperture is found to be 2 2 0 Find the radius of aperture in the sheet a

A conducting dise of conductivity o has radius a and thickness A uniform magnet field B is applied in a direction perpendicular to the plane of the disc If the magnetic field changes with time at the rate of dB dt then the power dissipated in the disc due t the induced current A dB 8 dt B Ta d C dB 12 dt 4 dt D do dB 6 dt

A solid nonconducting sphere radius 12 cm has a charge of uniform density 30 nC m distributed throughout its volume Determine the magnitude of the electric field 30 cm from the center of the sphere Select one a 21 7 O b 18 9 O c 24 2 O d 27 3

hollow conducting sphere of inner radius R an outer radius 2R is given a charge Q as shown in th figure then the 2R CR 1 Potential at A and B is different 2 Potential at O and B is different 3 Potential at O and C is different 4 Potential at A B C and O is same

Three particles each having a charge Q are placed on the three vertices A B C of a square of side a The electric field at the centre of the square is 4 Q along OB A 4t Eo a 1 Q B 4750 2 2 along OD C 1 2Q 4no a 1 along OB 2Q D 2along OD 4 a D

A test charge is moved from lower potential point a higher potential point The potential energy of test charge will a remain the same b increase c decrease d become zern

It is said that any charge given to a conductor comes to its surface Should all the protons come to the surface Should all the electrons come to the surface Should all the free electrons come to the surface

Consider two charged metallic spheres S and S of radii R and R respectively The electric fields E on S and E on S on their surfaces are such that E E R R Then the ratic V on S V on S of the electrostatic potentials on each sphere is 1 R R 2 R R

6 Quantisation of charge implies 1 Point Charge does not exist Charge exists on particles There is a minimum permissible magnitude of charge Charge can t be created 7 When a body is charged by induction then the body 1 Point becomes neutral does not lose any charge loses whole of the charge on it loses part of the charge on it

2 SI unit of permittivity of free space is 1 Point Farad Weber C2N 1 m 2 C2N 1 m 1 3 Electric field lines provide information about 1 Point field strength direction nature of charge all of these

A particle of mass m and charge q is projected in a region where an electric field given by E Ei exists with a velocity vo from the origin at time t 0 then choose the correct statements assuming m v 2qEomxo radius of curvature of the particle when its x coordinate becomes Xo is 2x0 radius of curvature of the particle when its x coordinate becomes xo is 8 2x0 speed of the particle when its x coordinate becomes xo is 2V0 speed of the particle when its x coordinate becomes Xo is 2vo

Find the electric field at point P on the perpendicular bisector of a uniformly charged thin wire of length 2L carrying a charge Q The distance of the point P from 1 4 0 the center of rod is L 3 3 K 2L L 3 P

Consider three equipotential surfaces of field produced by q point charge A small point charge q is taken slowly along two paths from A to B and A to C then Work done by electric field in moving it from A to B is ve Work done by electric field in moving it from A to B is ve Work done by an external agent in moving it from A to C is ve The correct order of potential will be V3 V V B V A V 4

3 Two spheres each of radius R and carrying equal and opposite uniform charge densities are placed such that they overlap as shown in Fig 3 Find the electric field in the region of overlap and analyses the properties of the same

The spatial distribution of the electric field lines due to charges A B is shown in figure Which one of the following statements is correct Question Type Single Correct Type 1 A is ve and B is ve and A IBI 2 A is ve and B is ve A B 3 Both are ve but A B Roth are ve but A R B

ams ments zor Potential at the centers of two very thin spherical shells A and B of equal radii and equal masses are VA and VB respectively Mass of shell A is uniformly distributed whereas distribution of mass on shell B is non uniform Potential at infinity is zero then O VA VB O VA VB OVA VB We cannot compare VA and VB

Animal cells have a membrane that separates the interior of the cell from the outside environment Typically an electric potential difference exists between the inner and outer surfaces of the membrane Consider one such cell where the magnitude of the potential difference is 53 mV and the outer surface of the membrane is at a higher potential than the inner surface A potassium ion K is initially just inside the cell membrane initially at rest How much work in 3 is required for a cell to eject the ion so that it moves from the interior of the cell to the exterior

A carbon resistance has value R 2 4 5 ther sequence of colour code is 1 Red Yellow Silver Golden 2 Red Orange Silver Golden 3 Red Yellow Golden Golden ge Golden Silver

Two point charges are kept at a certain distance from one another The graph represents the variation of the potential along the straight line connecting the two charges 1 q and q both are positive and q q 2 q and q both are positive and q ql 3 Both charges have opposite nature and lq qal 4 Both charges have opposite nature and lq kqal

D A dipole is placed at origin of coordinate system shown in figure then the electric field at p P 0 y is 1 4 3 P 0 y up 1 p i 2 2y 1 p i 2j 2 4 e 2y 4TEO 1 p 2 y 1 g i 27

Assertion The electric flux of the electric field E dA is zero The electric field is zero everywhe on the surface Reason The charge inside the surface is zero

In the circuit shown here E E E3 2 V and R R 4 ohms The current flowing between points A and B through battery E is 8 Ei A E 2 3 1 zero 3 2 A from B to A R wwwww R www B 2 2 A from A to B 4 none of the above

9 Assertion When a charged body is brought near to an uncharged conducting body equal and opposite charge is induced on the nearer surface of the conducting body Reason Net electric field inside the conductor is zero

O 85 a wire as shown in the figure is then which of the following statement s is are correct a Electric field at the centre is 280 R b Electric field at the centre of the loop is CBSE Sample Paper Physics 2 TER

31 The potential at a point x measured in m due to some charges situated on the x axis is given by 20 V x volt x 4 The electric field E at x 4 m is given by a V m and is in positive x direction 3 c 100 V um and is in positive x direction b 1V m and is in negative x axis 9 d V m and is in negative x direction ution Papers 1181

In the diagram shown there is a square inside there is another square and inside it there is another square and so on On the vertex of each square a charge is placed On the vertex of the Nth square the charge Q 2N is placed If the dimension of the outermost square is L and the number of the squares formed in this manner is infinite then what will the potential at the centre SSR A 2Q 2 1 TEL B Q 2 1 L C 4Q 2 1 L D None of these

Suppose there is a uniform electric field E 50 V m If a negative char particle moves in the y direction then its electric potential energy 1 Increases 2 Decreases 3 Remains constant 4 First increase then decrease

A uniformly charged hemisphere of radius b and charge density p has a hemispherical depression of radius a a b 2 cut from its centre If the electric field at the then n centre of the depression is P n

28 Two point charges of equal magnitude but opposite polarity are kept at po A 0 0 3a and B 0 0 3a respectively The work done by the ele field when another positive point charge is moved from P 2a 0 0 Q 0 2a 0 is 1 Positive 2 Negative 3 Depends on the path followed

Q1 A positive point charge of Q coulomb is placed at the centre of a sphere of radius R The Electric fl through the surface is X units If the radius of the sphere is doubled the changes in electric flux will a X 2 b 2X d zero

28 Answer Q 28 29 30 by appropriately matching the information given in the three columns of the following table Consider a non conducting ring of radius r and mass m and a particle of same mass both at rest in free space The particle is on the axis of the ring and far away from the ring An amount of positive charge is uniformly distributed on the ring and the particle is given a positive charge q The particle is imparted a velocity v towards the centre of the ring Consider the consequences given in the columns and answer the following questions Column 1 I Maximum speed of the ring is v II Maximum speed of the ring is v 2 III Maximum speed of the ring is Qq REOmrv IV Maximum speed of the ring 1 is 2 Qg Emrv i Column 2 Minimum speed of the particle is v 2 ii Minimum speed of the particle is zero iii Minimum speed of the particle is 1 Qq iv Minimum speed of the particle is Qq mrv P zero respectively Q Final speed of the ring R Column 3 Final speed of the ring and particle is v and IS S Which of following options is the correct representation if v A II i S B 1 ii P C III iv R and particle is zero and v respectively Final speed of the ring and particle is v 4 and 3v 4 respectively Final speed of the ring and particle is v 2 for both Qq 2 omr D IV iii Q

A proton travels through a uniform electric field E 20 000V m for a distance of d 5 m What is the amount of kinetic energy gained by the particle What is the final velocity of the proton after it leaves the electric field region if it started from rest Proton mass m 1 672x10 27 kg p Proton charge a 11602x10 19 C

Two similar spheres are not experiencing any force initially Now when 10 3 electrons ar transferred from one sphere to other they experience the force of 0 25 N What is the distance between the spheres

Please provide Handwritten answer Consider the situation shown in the figure The three point charges are identical and each has a mass of 0 1278 kg The length L 30 5 cm and theta 45 Find the value of q

A uniformly origin A uniformly kept with its centre at x 5m both are non conducting charged thin shell of charge 20 C mass 1kg radius 1m is kept with its centre at charged sphere of mass 2kg and radius Im having a total charge of 5uC is AL CLA 19 Select the CORRECT statement s A For finding potential at the origin we need to know the charge on shell as well as on the sphere B For finding the electric field at the origin we need to know the charge on the shell as well as on the sphere C For finding the potential at the origin we need to know the charge on the sphere but not on the shell D For finding the electric field at the origin we need to know the charge on the sphere but not on the shell

About 100 years ago JJ Thomson was trying to figure out a stable model of an atom In the process be posed a problem which has since then been known as Thomoson s problem Given a rigid hollow sphere of radius R we want to put in N electrons inside so that the potential energy of system is minimum For N 2 the solution is obvious Electrons should be at the ends of the diameter For N 3 4 5 the problem is solved and the solution is shown here For a general N the problem has not been solved till date 26 N 3 A 6 5 vertices of equilateral triangle How much extra work has to be done to increase N from N 3 to N 4 OLE vertices of a regular tetrahedron N 4 B 3 2 ke SSROOM D None of these

For the isolated charged conductor shown in th figure if the electric field at point A and B is B and Eg respectively then NCERT Pg 6 B 1 EB EA 2 EA EB A

If two identical spheres having charge 16 uC and 8 uC are kept at certain distance apart then the for F They are touched and again kept at the same distance the force becomes 2 1 F F 18 F 3 8 4 2

28 The figure shows a charge g at point P held in equilibrium in air with the help of four q charges situated at the vertices of a square The net electrostatic force on q is given by PQ 4 a Newton s law c Principle of superposition 9 b Coulomb s law d Net electric flux out the position of q

A pattern is drawn for equi potential surfaces for two positive charges Selec the correct option a pattern is correct b pattern is wrong c It is correct only for one positive charge d pattern can t be drawn

Two identical point charges are moving in free space when they are 60 cm apart their velocity vectors are equal in modulus and make angles of 45 from the line joining them as shown in the figure at this instant their total kinetic energy i equal to their potential energy what will be the distance of closest approach between them 45 60 cm 45

This section contains 25 questions Attempt any 20 questions from this section Read More Two beams of electrons and protons move parallel to each other in the same direction then they Attract each other Repel each other No relation

2 i A closed Gaussian surface consisting of a hemisphere and a circular disc of radius R is placed in a uniform electric field E as shown in figure The circular disc makes an angle 0 30 with the vertical What would be the flux of the electric field vector coming out of the curved surface of the hemisphere 6 E

Three identical thin uniformly charged filaments are fixed along three sides of a cube as shown in the figure Length of each filament is I and line charge density on each of them is Determine electric field at the centre of the cube The cube is a geometrical construct and not made of any matter 8

2 A rod of length is rotating about an axis at P distance from one end as shown in figure If angular speed of rod is w and magnetic field is B out of the page find emf developed between end points of rod OB 12 1 Bw1 3 Bol 3 B 2 Bwf 4 Zero

In a free space a thin rod carrying uniformly distributed negative charge q is placed symmetrically along the axis of a thin ring of radius R carrying uniformly distributed charge Q Mass of the rod is m and length is 2R The ring is fixed and the rod is free to move The rod is displaced slightly along the axis of the ring and then released If the period T of the small amplitude oscillations of the rod is 2 2 mR Qq n R then find the value of n q R

5z An electric field in free space is E at the origin A The charge stored in this sphere is 810 C k V m consider a sphere of 3 m radius centered Eo B The energy stored in this sphere is C The charge stored in this sphere is D The energy stored in this sphere is 425 2880 405n C 425T 168 x 38 J x38 J

b The three charges 4 C 3 C and 5 C are attached to the vertices of an equilateral triangle whose sides are 10 cm long as below Calculate the magnitude of the net electric force on 4 C charge 5 C 1 3 C

Suppose that 3 point charges qa qb qc are arranged at the vertices of a right angled tri angle what is the absolute electeic potenti al at the position of the third charge if qa 6 micro coulomb qb 4 micro coulomb qc 2 micro coulomb a 4m b 3m suppose that the third charge is repelled to i nfinity by the combined electric field of the other two charges which are held fixed what t is the final kinetic energy of third charge

q1 10 0 As shown in the figure a point charge q 1 x 10 C is placed at the origin in x y plane and another point charge q 3 x 10 6 C is placed at the co ordinate 10 0 In that case which of the following graph s shows most correctly the electric field vector in E in x direction fi foc Crafult x face E A C 1x 106 C x y 3 x 10 C 10 0 4 4 of 10 0 E Hp 110 01 B D Ex E fact 10 0 110 0