Electric Field and Potential Questions and Answers

f COLUMN I B P A P P P C P R R R q S f and R variable resistance p 9 r COLUMN II R sh E E M R st E r 5 M r 5Q R sh r 32 R s R 0 R 392 R 5 Q R 59

Three charges are positioned as follows 91 2 at A 3 1 0 92 2 at B 1 3 0 93 at C 3 3 0 Assuming that the charges are static and fixed in space what should the charge q3 be so that the electric field intensity at 0 0 0 is zero E

2 3i j 4 1 6i 2j 3 6i 2j Two particles of masses m and 2m with charges 34 24 and 2q are placed in a uniform electric field E and allowed to move for the same time The ratio of their kinetic energies will be 1 2 1 2 8 1 3 4 1 4 1 4 1 3i j 3 6i 2j 2 3i j 4 1 6i 2j 2 2q8 afa sura ya ats fear and at gre fre a farma 1 2 1 2 8 1 3 4 1 4 1 4

25 E x graph for the uniformly charged ring will be 25 E on y axis 2 X LEADER TEST SERIES JOINT PACKAGE COURSE 32844 XX Ey 0999DMD310320001

3 14 4 19 Number of electrons in one coulomb of charge 18 will be 1 5 46 1029 3 1 6 10 9 2 6 25 10 4 9 x 10 3 14 1 5 46 10 3 1 6 10 4 19 2 6 25 10 4 9 10

D The angles of inclination of the suspended 20 o a fer 306 at 0 0 charged pendulum are 30 60 due to electric field of the infinite sheets of surface charge densities and a respectively then a a AN AN 60 2 3 2 3 4 1 3 4 1 3 1 3 3 1 3 T 1 3 3 1 3

In a region of uniform field as an electron travels from A to B it slows from UA 6 1 x 106 m s to up 4 5 106 m s What is its potential change AV VB VA in volts A 18 B 18 C 48 Correct Answer

Which of the following is a property of equipotential surfaces 0 77 Mark O The direction of electrostatic field will be perpendicular to the equipotential surface The potential difference between any two points on an equipotential surface is zero For a point charge the equipotential surfaces will be concentric spheres All the statements above are correct

A thin metallic spherical shell carries a charge Q on it A point charge q is placed at the centre of the shell and another charge q is placed outside it The net force on the charges at the centre and outside are respectively Q q 9 1 Zero towards right 2 Towards left towards right 3 Zero zero I CI 9

Two small balls having equal positive charge Qeach are suspended by two insulating strings of equal length L from a hook fixed to a stand The whole set up is taken in a satellite into space The tension in each string is O o O C 1 Q 4T 1

An electric dipole of dipole moment Pis placed perpendicular to electric lines of force of electric field E then the work done in slowly deflecting it through an angle of 180 is O PE O 2 PE O 2PE

Two identical pendulum A and B are suspended from the same point The bobs are given positive charges with A having more charge than B They diverge and reach at equilibrium with A and B making angles 0 and 0 with the vertical respectively Then A 0 0 2 B 0 0 C 0 0 1 D Tension in A is smaller than in B A B A B You Missed

Q19 A solid sphere of uniform density and radius 4 units is located with its centre at the origin O of coordi nates Two spheres of equal radii 1 unit with their cen tres at A 2 0 0 and B 2 0 0 respectively are taken out of the solid sphere leaving behind spherical cavities as shown in the figure Then 1993 Y B the gravitational field due to this object at the ori gin is zero B the gravitational field at the point B 2 0 0 is zero the gravitational potential is the same at all points on circle y 22 36 the gravitational potential is the same at all points on circle y 2 4

Two thin wires rings each having a radius R are placed at a distance d apart with their axes coinciding The charges on the two rings are q and q The potential difference between the centres of the two rings is 2005 1 QR 4d 3 zero 2 4 Q 1 2 ER Q 1 4 ER 1 R d 1 R d

Figure shows electric field lines in which an electric dipole p is placed as shown Which of the following statements is correct 9 a The dipole will not experience any force b The dipole will experience a force towards right c The dipole will experience a force towards left d The dipole will experience a force upwards

An a particle accelerated through V volt is fired C towards a nucleus Its distance of closest approach is r If a proton accelerated through the same potential is fired towards the same nucleus the distance of closest approach of the proton will be 3 1 2 1 r 2 2 E XXL 44 Mx 4

You have 10 23 carbon atoms Imagine that all the nuclei are put at north pole of the earth and electrons at the south pole of the earth radius 6400km The n force of attraction between the charg es approximately is A 5 10 5 N B 2 10 6 N C 13 6 10 3 N D 2 10 5 N

A plastic rod of length 1 0 m carries uniform positive charge 4 0 C on half of its length and uniform negative charge 4 0 C on the remaining half of its length Find magnitude of it s net dipole moment in C m

Two spheres A and B of exactly same initial mass are given equal positive and negative charges respectively Their masses after charging Remains unaffected Mass of A mass of B Mass of A mass of B Nothing can be said

25 Eight equal point charges are placed at corners of cube of side length a The potential and electric fie magnitude at the centre of cube will be 4q 1 3 RE 3 0 0 0 4q 4q 2 3 x 3m a 4 0 4q 3 m

23 If the electric potential in a region is represented as V 2x 3y 4z Then electric field vector will written as 1 2 3 4k 3 2 3 4k 2 21 3 4K 4 2 3 4k

2016 2017 2 A particle having charge equal to proton and mass 12 10 21 g is thrown parallel to plates as shown in the figure Value of electric field between plates is 1 5 104 V m and length of plates is 10 cm The least initial velocity given to particle so that it is able to come out of the plates is 1 cm 1 cm U 1 4 104 m s 3 2 104 m s 10 cm E 2 3 104 m s 4 1 104 m s

21 The flux of electric field through the circular region of radius r as shown in the figure is 1 2 to r 0 2 Zero 2 r C m

1 Equipotential surfaces associated with an electric field which is increasing in magnitude along x direction are 1 Planes parallel to x z plane 2 Coaxial cylinders of increasing radii around x axis 3 Planes parallel to y z plane 4 Planes parallel to x y plane

4 Planes parallel to x y plane 42 An electric dipole is kept in the field of a point charge Q as shown in figure If dipole is at origin then net force on the dipole is Y Point charge O P Dipole 1 Along negative x axis 2 Along positive y axis 3 Zero 4 Along positive x axis Telegram nega Space for Ro

5 Figure shows two conducting thin concentric shells of radius r and 3r The outer shell carries charge q Inner shell is neutral The charge that flows from inner shell to the earth after the switch S is closed is q tionpaper 1 q 3 03 3r 2 Zero 2q 3

19 Four similar point charges q are located at t vertices of a regular tetrahedron of edge length a T interaction energy of the system of charges is 3q 1 ATE 3 q O O 2 400 3q Telegram

w 7 A charge q is uniformly distributed over a quarter circular ring of radius r The magnitude of electric field strength at the centre of the ring will be 29 Mar 4 9 3 2 2 4T of 4

13 Four point charges are placed on vertices of a square If all the charges are brought to any one of the vertices The change in potential at the centre of square due to this would be 1 Dependent on polarity of charges 2 A non zero constant 3 Zero 4 Infinite

For the circuit Figure 1 take 300 V R 4 0 kn R 6 0 kn and assume the capacitor is initially uncharged Figure R ww ww R 1 of 1

x An infinitely long solid cylinder of radius R has a uniform volum spherical cavity of radius R 2 with its centre on the axis of the cylinder as shown in the figure The magnitude of the electric field at the point P which is at a distance 2R from the axis of the cylinder is given by the expression The value of k is 1 R 2 AZ R P 2R Y 23pR 16ko

1 As shown in the figure below the particle of mass m and charge q will touch the infinitely large plate of uniform charge density o if its velocity v is more than Given that oq 0 0 load 6 q m d 2 20qd m o bunu J

Two long line charges of linear charge densities and A respectively are fixed r distance apart as shown Electrostatic force per unit length on it is equal to 1 H 41 0 2 1 2 2 r 1 X X 2 4 K 2 1 2 2 2 2 2 1 2 22

charge densities at point P and Q are op and o respectively If 10 C charge is moved from centre C to point S then S 211 C 1 op will increase and will decrease 2 op will decrease and will decrease 3 op will increase and oo will remains unchanged 111 7 unchanged

Two identical balls having like charges and placed at a certain distance apart repel each other with a certain force They are brought in contact and then moved apart to a distance equal to half their initial separation The force of repulsion between them increase 4 5 times in comparison with the intital value The ratio of the final charges of the balls is Question Type Single Correct Type 12

A solid conducting sphere of radius 2R carrying charge Q is surrounded by two point charges Q and 2Q as shown in the figure The electric field at point P due to the induced charges on conducting sphere is 3R R 8 8 2Q 3R

Two equal point like positive charges A and B are fixed on the y axis equidistant from the origin What can you say for the net electrostatic force on a small electrically neutral conducting rod placed on the x axis as shown in the figure A B C

A square of side a is lying in xy plane such that its two adjacent sides are lying on the x and y axes If an electric field E Ek is applied on the square then the flux passing through the square is Only one correct answer A Eoa i

A metal sphere A of radius r charged to a potential is enveloped by a thin walled conducting spherical shell B of radius r Then potential of the sphere A after it is connected to the shell B by a thin conducting wire will be 1 6 5 1 3 1 1 41 B 4 1 2 4 r r 1 1

Read the following source and answer any four out of the following questions Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field There are two types of charges positive and negative charges Also like charges repel each other whereas unlike charges attract each other i Charge on a body which carries 200 excess electrons is a 3 2 x 10 18 C b 3 2 x 10 18 C c 3 2 10 17 C d 3 2 10 17 C

7 A point charge is kept at the mid point between two large parallel grounded conducting plates Assuming no gravity the charge is displaced a little towards the right plate The charge will now a stay where it is b move towards the right plate c move towards the left plate d oscillate between the plates

Find equivalent capacitance between A B Options 1 C 2 O 2 C 3 O 30 4 O 4 C HH X C C 2C 4C Section series

Four positive point charges of charge q each are placed at the corners of a square of sides a The square lies in the y z plane with its center at the origin Now if a uniformly charged rod of length 1 and charge Q is placed along the x axis form x0 to x0 then find expression of the electric force the four point charges exert on the charged rod

Two small spherical similar charged ball ve are tied with thread with the same point A as shown in figure q A 9 If one more ve similar charged ball is tied with point A distance between this two charges will not change In case of one more ve charge distance will change

Assertion A If there exists a coulomb attraction between two bodies both of them may not be charged Reason R In coulomb attraction two bodies are oppositely charged a Both A and R are true and R is the correct explanation of A c A is true but R is false b Both A and R are true but R is not the correct explanation of A d A is false but R is true

wo similar charge of Q as shown in figure are placed at A and B q charge is placed at point C midway between A and B q charge will oscillate if 69 B It is moved towards A It is moved towards B It is moved upwards AB

Q Assertion A For charges to be in equilibrium sum of the forces on a charge due to rest of the two charges must be zero Reason R The resultant force on a charge can be calculated using superposition principle

TYPE questions Each question has 4 choices 1 Read More A hollow charged metal sphere has radius R If the potential difference between the surface and a point at distance 3R from centre is V then the electric field intensity at a distance 5R from surface is V 6R V 12R V 24R

Even number of infinite concentric circular arcs of same angular span 0 carry uniform linear charge densities A and alternatively as shown in figure Their radii are R 2R 3R respectively potential at their common centre is The 3 2 0 In2 41 En 20 Inl 41 E use 1 1A Common Test 8 36 2 0 R 2 R 20 In 2 2n E Telegram 4 None of these 29 No questi tema R 2R 3R 13 1 3 for THE 0 In2 41 E 20 in 1 4 AGRA fangen 2 0 R R 4 20 In 2 2n E 1001CMD302120020 Hindi 07102020

TYPE questions Each question has 4 choices 1 Read More Two small balls having equal positive charge Q each are suspended by two insulating strings of equal length L from a hook fixed to a stand The whole set up is taken in a satellite into space The tension in each string is O o 1 Q 4TE 1 1 Q 4 2L 1 A a