Page 1 :
PHYSICS, , , , >> Multiple Choice Questions (MCQs) \\—, , DIRECTIONS :, , , , section contains multiple choice ques, , Each question has four choices (a), (b), (c) and (d) out of which, , only one is, , rect., , , , Two small spheres each having the charge +Q are, suspended by insulating threads of length Z. froma hook., This arrangement is taken in space where there is no, gravitational effect, then the angle between the, two suspensions and the tension is in each, thread., , so,, , i, ®) "aney 2, , (a) 180°,, 4meg (21)°, , , , , , 2 2, ig @ 10,2, , (c) 180°,, © 4néy 2 4ney 2, , , , , , Two equal point charges each of 31C are separated by a, , certain distance in metres. If they are located at, , (7+ 7+ Mand (2i +3 + £), then the electrostatic force, , between them is, , (a) 9x 103N (b) 16x 103N, , (© 103N @ 9x10?N, , A body is positively charged, it implies that, , (a) there is only positive charge in the body, , (b) there is positive as well as negative charge in the, body but the positive charge is more than negative, charge, , (c) there is equal positive and negative charge in the, body but the positive charge lies in the outer regions, , (d)_ negative charge is displaced from its position, , On rubbing, when one body gets positively charged and, , other negatively charged, the electrons transferred from, , positively charged body to negatively charged body are, , (a) valence electrons only, , (b) electrons of inner shells, , (c) both valence electrons and electrons of inner shell, , (d) yet to be established, , Three charges +g, +2g and +4g are connected by strings, , as shown in the figure. What is ratio of tensions in the, , strings AB and BC?, , Electric Charges, and Fields, , ig ¥2q +4q, @ 1:2 ) 1:33 @ 2:1 @ 3:1, Two charge q and —3q are placed fixed on x-axis, separated by distance d, Where should a third charge 2q, be placed such that it will not experience any force?, , , , , , , , q, Aw————d. B, d-V3d d+v3d, {a) a (b) a, dt3d d-3d, () 2 @ 2, , ‘Two positive ions, each carrying a charge g, are separated, by a distance d. If F is the force of repulsion between the, ions, the number of electrons missing from each ion will be, (e being the charge of an electron), , Aney Fd™, @ — z—, , ee, , Ane F, , , , (o), , A large nonconducting sheet M is given a uniform charge, density. Two uncharged small metal rods A and B are placed, near the sheet as shown in figure. Then, , (a) Mattracts A M, (b) Mattracts B, (ce) Aattracts B, , (d) All of these, Three charges -q, , +g, and ~g, are place as shown in the, figure. The x - component of the force ong, is proportional to, , , , A B, CoC 4, , , , ¥, -4,, x), sg b, N <— =>, “4, ta, X

Page 2 :
10., , 13., , 15., , , , A total charge Q is broken in two parts Q, and Q, and they, are placed at a distance R from each other. The maximum, force of repulsion between them will occur. when, , @ =2.a-0-2 w a-2.0-0-2, , Q 3Q Q Q, © QA @ oleae ers, Figure shows the electric lines of force emerging from a, charged body. If the electric field at A and Bare £’, and E,, respectively and if the displacement between A and Bis r, then, , , , (a) E,>Ep, ) Ey < Ep, £, © By-=®, E£, () Ey=—, , r, , Anlectric dipole with dipole moment 4 x 10-9 cm isaligned, , at 30° with the direction of a uniform electric field of, , magnitude 5 x 104 NC-!. The torque acting on the dipol, , (a) 1*104Nm (b) 5 10-8Nm, , () 11x 10-'2Nm (a) 25% 101°Nm, , The electric field at a point on equatorial line ofa dipole, , to direction of the dipole moment., , (a) will be parallel, , (b) will be in opposite direction, , (c)_ will be perpendicular, , (d) are not related, , The electric field intensity just sufficient to balance the, , earth’s gravitational attraction on an electron will be: (given, , mass and charge of an electron respectively are, , 9.1107 !kg and 1.6x107C.), , f@) $.6* to NC (b) 48x Lo SN/C, , (©) -1.6% 10 9 NIC (d) 3.2% 10-9 N/C, , Which one of the following is not a property of field, , lines., , (2) Field, breaks., , (vb) Two field lines cannot cross each other., , (©) Field lines start at positive charge and end at, negative charge, , (@ They form closed loop, , If a dipole of dipole moment p is placed in a uniform, , electric field E , then torque acting on it is given by, , b+) t=pxE, , (© t=prE @) %=p-E, , If E,, be the electric field strength of a short dipole at a, , point on its axial line and £, that on the equatorial line, , at the same distance, then, , @ £5 2£,, , ‘a, , © E,= Ep, , , , lines are continuous curves without any, , , , , , t=, , () £,= 28,, (d)_ None of these, , 18., , 20., , 21., , 22., , 23., , Physics, , Which of the following graphs shows the correct variation, in magnitude of torque on an electric dipole rotated in a, uniform electric field from stable equillibrium to unstable, equillibrium?, , @ ft ® f, : 1, g 3, z g, 5 a, , Angle rotated@ > Angle rotated0—>, , of, t, é 8, z, : E, , , , , , , , Angle rotated0—>, The electric intensity due toa dipole of length 10 cm and, having a charge of 500 iC, at a point on the axis at a, distance 20 cm from one of the charges in air, is, (a) 6.25% 107N/IC (b) 9.28 107 NIC, ( 13.1* 10" NC (d) 20.5% 10’N/C, A tod of length 2.4 m and radius 4.6 mm carries a, negative charge of 4.2 x 10-7 C spread uniformly over, it surfice. The electric field near the mid-point of the, rod, at a point on its surface is, (a) -8.6x 10ONC! (b) 86x 10°NC?, () -6.7* 105NC! @) 6.7% 109INCT, The total electric flux emanating from a closed surface, enclosing an a-particle is (e-electronic charge), , 2e ege, , @®@ 2 (b) @ —|, A square surface of side L meter in the plane of the paper, is placed in a uniform electric field £ (volt/m) acting along, the same plane at an angle 9 with the horizontal side of, the square as shown in Figure. The electric flux linked to, , Angle rotated @—>, , (c) €&, , , , , , , , the surface, in units of volt. 2, is g, (a) EL? Vas, (b) EL? cos@, () EL?sing, , , , (d) zero fo, , The E-rcurve for an infinite linear charge distrib, be, , jon will, , , , , , 4 +, @ & ) F, > TS, ot LL @ t-——, 5 =

Page 3 :
Electric Charges and Fields, , 24,, , 25., , 26., , 27., , 28., , 29., , 30., , 31., , Al the centre of'a cubical box + Q charge is placed. The, , value of total flux that is coming out a wall is, , (a) Q/s, (b) Q/38, (©) Q/4s, (d) Q/ be,, , The Gaussian surface, , (a) can pass through a continuous charge distribution, , (b) cannot pass through a continuous charge, distribution., , (c) can pass through any system of discrete charges., , (@) can pass through a continuous charge distribution, , as well as any system of discrete charges., , Ina region, the intensity of an electric field is given by, , B = 21+3)+& in NC. The electric flux through a surface, , S=10i m? in the region is, , (@) SNmCt (6) 10Nm?c!, , (©) 1SNm?c-! (@) 20Nm?c-!, , In the figure the net electric flux through the area 4 is, , =E-A when the system is in air. On immersing the, , system in water the net electric flux through the area, (a) becomes zero, , (b) remains same, (©) increases x, (@) decreases, A charge q is placed at the centre of the open end of a, cylindrical vessel. The flux of the electric Geld through the, surface of the vessel is (a) zero q, (b) ae,, (©) qe,, (d) 2q/e,, Ifthe electric flux entering and leaving an enclosed surface, respectively is @, and 4), the electric charge inside the, surface will be, @) (ht o)*e, (©) @y~b)*&, (©) (0) +) *& @) ()-o)* 8,, If the net electric flux through a closed surface is zero,, then we can infer [CBSE 2020], (a) no net charge is enclosed by the surface, (b) uniform electric field exists within the surface., (c) electric potential varies from point to point inside, , the surface., (d) charge is present inside the surface., In figure two positive charges q, and q, fixed along the yaxis, exert a net electric force in the+ x-direction on a charge, q, fixed along the x-axis. Ifa positive charge Qis added at, (x, 0), the foree on q,, (i), , oe, , , , Is, , 32,, , 34,, , , , (a) shall increase along the positive x-axis, (b) shall decrease along the positive x-axis, , {c) shall point along the negative x-axis, , (d)_ shall increase but the direction changes because of, the intersection of Q with q, and q,, , A point positive charge is brought near an isolated, conducting sphere (figure). The electric field is best given, by, , {a) (b) () (a), The electric flux through the surface, , s, @ (ii) (iil) (iy, (a) in Fig. (iv) is the largest, (0) in Fig. (iii) is the least, (c)_ in Fig. (ii) is same as Fig, (iii) but is smaller than, Fig. (iv), (d)_ isthe same for all the figures, , Five charges qj. 49, 43.44. and q, are fixed at their positions, as shown in Figure, S is a Gaussian surface. The Gauss’, , 4, , , , law is given by [EdS=—+. Which of the following, , , , statements is correct?, , , , , , “qs *%, , , , , , , , , , (a) E on the LHS of the above equation will have a, contribution from q), qs and q,, q5andq; while qon, the RHS will have a contribution from qy and qy only, , (®) E on the LHS of the above equation will have a, contribution from all charges while q on the RHS will, have a contribution from qy and q, only, , (©) Fon the LHS of the above equation will have a, contribution from all charges while q on the RHS will, havea contribution from q), 43 and qs., , (d) Both E on the LHS and q on the RHS will have, contributions from qy and qy only

Page 4 :
35., , 36., , 38., , 40., , 41,, , 42,, , Figure shows electric field lines in which an electric dipole, P is placed as shown. Which of the following statements, is correct?, , 43., , Peep, (a) The dipole will not experience any force, (b) The dipole will experience a force towards right, (c) Thedipole will experience a force towards left, (d) The dipole will experience a force upwards 44., A point charge + q is placed at a distance d from an isolated, conducting plane. The field at a point P on the other side, of the plane is, (a) directed perpendicular to the plane and away from, the plane, directed perpendicular to the plane but towards the 45,, plane, (©) directed radially away from the point charge, (d)_ directed radially towards the point charge., Ahemisphere is uniformely charged positively. The electric, field ata point ona diameter away from the centre isdirected 46,, (a) perpendicular to the diameter, (b) parallel to the diameter, (c) atan angle tilted towards the diameter, (d) atan angle tilted away from the diameter, Among two discs A and B, first have radius 10 om and 47,, charge 10 \1C and second have radius 30 cm and charge, 10°5C. When they are touched, charge on both q, and dp, respectively will, be, (@) dy=2.75uC, qg=3.15 pC, ) qq=L.09nC, qy=1.53nC 48., , © a= 4g =5-5uC, (d)_ None of these, , Figure shows some of the electric field lines corresponding, to an electric field. The figure suggests that, , (@) E,>Ep> Ee, , Bi eB, fe, , © E,=Eo>Ep, , (b), , 49,, , @) Ey=Ee<Dg, The surface density on the copper sphere is. The electric, , field strength on the surface of the sphere is, , @ o (bo) o2 (©) o/28, (d) Qe, , When a body is charged by induction, then the body 50., (a) becomes neutral, , (b) does not lose any charge, , (c)_ loses whole of the charge on it, , (d) loses part of the charge on it, , Quantisation of charge implies, , (a) charge cannot be destroyed, , (b) charge exists on particles, , Physics, , (c)_ thereisa minimum permissible charge on a particle, , (d) charge, which is a fraction of a coulomb is not, possible., , For an isolated system, it is possible to create or destroy, , charged particle, but it is not possible to create or, , destroy., , (a) net charge of the system, , (b) charge on each particle, , (c) charge distribution of system, , (d) None of these, , When some charge is transferred to ...A... it readily gets, , distributed over the entire surface of ... 4... If some, , charge is put on ... B..., it stays at the same place., , Here, A and B refer to, , (a) insulator, conductor (b) conductor, insulator, , (c) insulator, insulator (@)_ conductor, conductor, , A positively charged rod is brought near an uncharged, , conductor. Ifthe rod is then suddenly withdrawn, the charge, , lefton the conductor will be, , (a) positive (b) negative, , () zero (a) cannot say, , Two spheres A and B of exactly same mass are given equal, , positive and negative charges respectively. Their masses, , after charging, , (a) remains unaffected — (b)_ mass of A> mass of B, , (c)_ massofA<massofB (d) Nothing can be said, , Coulomb's law is true for, , (a) atomic distances (= 107!! m), , (b) nuclear distances (= 10-15 m), , (c) charged as well as uncharged particles, , (d) all the distances, , In annihilation process, in which an electron anda positron, , transform into two gamma rays, which property of electric, , charge is displayed?, , (a) Additivity of charge, , (>) Quantisation of charge, , (c) Conservation of charge, , (d) Attraction and repulsion, , Which of the following statements is incorrect?, , (a) The charge g on a body is always given by q = ne,, where v7 is any integer, positive or negative., , (b) By convention, the charge on an electron is taken, to be negative., , (c) The fact that electric charge is always an integral, multiple of e is termed as quantisation of charge., , (d) The quatisation of charge was experimentally, demonstrated by Newton in 1912., , Which of the following statements is incorrect? Study of, , charges, by scientists, concludes that, , (a) there are two kinds of electric charges., , (b) bodies like plastic, fur acquire elecrtic charge on, rubbing., , (c) like charges attract, unlike charges repel each other., , (d) the property which differentiates two kinds of, charges is called the polarity of the charge.

Page 5 :
Electric Charges and Fields, , 51., , 52., , 53., , 54,, , SA,, , 56., , 57., , 58., , 59,, , 60., , What happens when some charge is placed on a soap, , bubble?, , (a) Its radius decreases (b)_Its radius increases, , (c) The bubble collapses (d) None of these, , Consider a neutral conducting sphere. A positive point, , charge is placed outside the sphere. The net charge on the, , sphere is then, , (a) negative and distributed uniformly over the surface, of the sphere, , (b) negative and appears only at the point on the sphere, closest to the point charge, , (c) negative and distributed non-uniformly over the, entire surface of the sphere, , (d) zero, , A charged particle is free to move in an electric field. It will, , travel, , (2) always along a line of force, , (b) _alonga lineof force, if its initial velocity is zero, , (c)_ alonga line of force, ifit has some initial velocity in, the direction of an acute angle with the line of force, , (d)_ none of the above, , If one penetrates a uniformly charged spherical cloud,, , electric field strength, , (@) decreases directly as the distance from the centre, , (b) increases directly as the distance from the centre, , (c)_ remains constant, , (d) None of these, , Electric lines of force about a negative point charge are, , (a) circular anticlockwise (b) circular clockwise, , (©) radial, inwards (@)_ radial, outwards, , Electric lines of force, , (a) exist everywhere, , (b) exist only in the immediate vicinity of electric charges, , (c)_ exist only when both positive and negative charges, are near one another, , (dare imaginary, , A region surrounding a stationary electric dipoles has, , (a) magnetic field only, , (b) electric field only, , (c)_ both electric and magnetic fields, , (dno electric and magnetic fields, , The electric field at a point on equatorial line ofa dipole, , and direction of the dipole moment, , (a) will be parallel, , (b) will be in opposite direction, , (c)_ will be perpendicular, , (d) are not related, , An electric dipole is placed at an angle of 30° to a, , non-uniform electric field. The dipole will experience, , (a) atranslational force only in the direction of the field, , (b) a translational force only in the direction normal to, the direction ofthe field, , (c)_ a torque as well as a translational force, , (d) a torque only, , The spatial distribution of electric field due to charges, , (A, B) is shown in figure. Which one of the following, , statements is correct ?, , , , , , 61., , 62., , 63., , 65., , 66., , 67., , A B, , (a) Ais +ve and B-ve, |A) > |B], (b) Ais—veand B +ve, |A|=|B], (c) Bothare+ve butA>B, , (d) Bothare —-ve but A> B, , In the figure, charge q is, placed at origin O. When the, charge qis displaced from its, position the electric field at, point P changes, , , , (a) at the same time when qis displaced., , OP., (b) atatime after ie where c is the speed of light., , | OPcos0, (c) atatime afiee ———., , OPsin®, , , , (d) atatime after, , An electric dipole is placed in a uniform electric field. The, , dipole will experience, , (a) a force that will displace it in the direction of the field, , (b) a force that will displace it ina direction opposite to, the field., , (c) atorque which will rotate it without displacement, , (A) _atorque which will rotate it and a force that will displace, It, , On decreasing the distance between the two charges of a, , dipole which is perpendicular to electric field and, , decreasing the angle between the dipole and electric field,, , the torque on the dipole, , (a) increases (b) decreases, , (c) remains same (d) cannot be predicted., , A sphere of radius R has uniform distribution of electric, , charge in its volume. At a distance x from its centre for x, , <R, the electric field is directly proportional to, , (a) x2 (b) Ix (c) x (@) x, , Inamedium of dielectric constant K, the electric field is E., , If €9 is permittivity of the free space, the electric, , displacement vector is, , oa Ew» F © 2, , & Keo, , Positive electric flux indicates that electric lines of force, , are directed, , (a) outwards (b) inwards, , (c)_ either (a) or (b) (d) None of these, , If the flux of the electric field through a closed surface is, , zero, then, , (a) the electric field must be zero everywhere on the, surface, , (b)_ the electric field may not be zero everywhere on the, surface, , (c) the charge inside the surface must be zero, , (d)_ the charge in the vicinity of the surface must be zero, , , , W Kegk