Q.1
Two spheres A and B of radius a and b respectively are at the same potential. The ratio the surface charge density of A and B is
  • a) a/b
  • b) b/a
  • c)a2 / b2
  • d)b2 / a2
Q.2
A uniform wire of length 5m is carrying a steady current. The electric field inside it is 0.2 V/m. The potential difference across the ends of wire is
  • a) 1.0 volt
  • b) 0.5 volt
  • c)0.1 volt
  • d)5 volt
Q.3
A charge is divided into parts q1 and (q-q1). What is the ratio q/q1 so that the force between the two parts placed a given distance apart is maximum?
  • a) 1:1
  • b) 2:1
  • c) 1:2
  • d) 1:4
Q.4
Let P(r)=Qr/ πR4 be the charge density distribution for a solid sphere of radius R and total charge Q. For a point 'p' inside the sphere at distance r1 from the centre of the sphere, the magnitudes of electric field is .. [ AIEEE 2009]
  • a)
    ch-13_qn-149choice_img_no1.png
  • b)
    ch-13_qn-149choice_img_no2.png
  • c)
    ch-13_qn-149choice_img_no3.png
  • d)zero
Q.5
A hollow metal sphere of radius 5cms is charged such that the potential on its surface is 10 Volts. The potential at the centre of the sphere is [ IIT 1983]
  • a) zero
  • b) 10 Volts
  • c)same as at a point 5 cm away from the surface
  • d)same as at a point 25 cm away from the surface
Q.6
Two point charges +q and -q are held fixed at ( -d,0) and (d,0) respectively of a x-y coordinate system. Then [ IIT 1995]
  • a)the electric field E at all points on the x-axis has the same direction
  • b) electric field at all points on y-axis is along x-axis
  • c)Work has to be done in bringing a test charge from ∞ to the origin
  • d)the dipole moment is 2qd along x-axis
Q.7
A parallel plate capacitor of capacitance C is connected to a battery and is charged to a potential difference V. Another capacitor of capacitance 2C is similarly charged to a potential difference 2V. The charging battery is now disconnected and capacitor are connected in parallel to each other in such a way that the positive terminal of one is connected to the negative terminal. The final energy of the configuration is [ IIT 1995]
  • a) zero
  • b) (3/2) CV2
  • c) (25/6) CV2
  • d) (9/2) CV2
Q.8
An electron of mass me initially at rest, moves through a certain distance in a uniform electric field in time tA proton of mass mp, also, initially at rest, takes time t2 to move through an equal distance in this uniform electric field. Neglecting the effect of gravity, the ratio t2 / t1 is nearly equal to [ IIT 1997]
  • a)1
  • b) ( mp / me)1/2
  • c)( me / mp)1/2
  • d)1836
Q.9
A non conducting ring of radius 0.5 m carries a total charge of 1.1×10-10C distributed non-uniformly on its circumference producing an electric field E everywhere in space. The value of the integral ( l=0 being center of ring) in volts is [ IIT 1997]
ch-13_que_no-154_img_no1.png
  • a) +2
  • b) -1
  • c)-2
  • d)zero
Q.10
Two identical metal plates are given positive charge Q 1 and Q2 ( Q2< Q1) respectively. If they are now brought close together to form a parallel plate capacitor with capacitor with capacitance C, the potential difference between them is [ IIT 1999]
  • a)
    ch-13_qn-155choice_img_no1.png
  • b)
    ch-13_qn-155choice_img_no2.png
  • c)
    ch-13_qn-155choice_img_no3.png
  • d)
    ch-13_qn-155choice_img_no4.png
Q.11
For the circuit shown in figure. Which of the following statement is true[ IIT 1999]
ch-13_que_no-156_img_no1.png
  • a) With S1 closed V1=15V, V2=20V
  • b) With S3 closed V1=V2=25V
  • c) With S1 and S2 closed V1=V2=0
  • d) With S1 and S3 closed V1=30V, V2=20V
Q.12
if a capacitor C, 3C, 5C ...∞ is one network and 2C, 4C, 6C ...∞ is another network are connected in series. If the effective capacitance of first network is C1 and that of network second be C2 then C1C2 /(C2 -C1) equal to
  • a) C / log2
  • b) log2/C
  • c) ∞
  • d) (log2)2 / C
Q.13
Three charges Q, +q and +q are placed at the vertices of a right-angled isosceles triangle as shown in figure. The net electrostatic energy of the configuration ia zero if Q is equal to .. [ IIT 2000]
ch-13_que_no-157_img_no1.png
  • a)-q / (1+√2)
  • b) -2q / (2+√2)
  • c)-2q
  • d)+q
Q.14
A parallel plate capacitor of area A, plate separation d and capacitance C is filled with three different dielectric materials having dielectric constants k1, k2 and k3 as shown. If a single dielectric material is to be used to have the same capacitance C in this capacitor, then its dielectric constant k is given by [ IIT 2000]
ch-13_que_no-158_img_no1.png
  • a)
    ch-13_qn-158choice_img_no1.png
  • b)
    ch-13_qn-158choice_img_no2.png
  • c)
    ch-13_qn-158choice_img_no3.png
  • d)
    ch-13_qn-158choice_img_no4.png
Q.15
Consider the situation shown in the figure. The capacitor A has a charge q on it whereas B is uncharged. The charge appearing on the capacitor B a long time after the switch is closed is ..[ IIT 2001]
ch-13_que_no-159_img_no1.png
  • a)zero
  • b)q/2
  • c)q
  • d)2q
Q.16
A uniform electric field pointing in positive x-direction exists in a region. Let A be the origin, B be the point on the x-axis at x=+1 cm and C be the point on the y-axis at y=+1cm. Then the potential at the point A, B, and C satisfy [ IIT 2001]
  • a) VA < VB
  • b) VA > VB
  • c) VA < VC
  • d) VA > VC
Q.17
Two equal point charges are fixed at x=-a and x=+a on the x-axis. Another point charge Q is placed at the origin. The change in the elecrical potential energy of Q, when it is displaced by a small distance x along the x-axis, is approximately proportional to [ IIT 2002]
  • a)x
  • b) x2
  • c)x3
  • d)1/x
Q.18
Two identical capacitors, have the same capacitance C. One of them is charged to potential V1 and the other VThe negative ends of the capacitor are connected together. When the positive ends are also connected, the decrease in the energy of the combined system is [ IIT 2002]
  • a)
    ch-13_qn-162choice_img_no1.png
  • b)
    ch-13_qn-162choice_img_no2.png
  • c)
    ch-13_qn-162choice_img_no3.png
  • d)
    ch-13_qn-162choice_img_no4.png
Q.19
A metallic shell has a point charge 'q' kept inside its cavity. Which one of the following diagram correctly represnets the electric lines of forces?
  • a)
    ch-13_qn-163choice_img_no1.png
  • b)
    ch-13_qn-163choice_img_no2.png
  • c)
    ch-13_qn-163choice_img_no3.png
  • d)
    ch-13_qn-163choice_img_no4.png
Q.20
Six charges of equal magnitude, 3 positive and 3 negative are to be placed on PQRSTU corners of a regular hexagon, such that field at the centre is double that of what it would have been if only one +ve charge is placed at R [ IIT 2004]
  • a) +, +, +, -, -, -
  • b) -, +, +, +, -, -
  • c) -, +, +, -, +, -
  • d) +, -, +, -, +, -
Q.21
A Gaussian surface in the figure is shown by dotted line. The electric field on the surface will be [ IIT 2004]
ch-13_que_no-165_img_no1.png
  • a)due to q1 and q2 only
  • b) due to q2 only
  • c)zero
  • d)due to all
Q.22
Three infinitly long charge sheets are placed as shown in figure. the electric field at point P is [ IIT 2005]
ch-13_que_no-166_img_no1.png
  • a)
    ch-13_qn-166choice_img_no1.png
  • b)
    ch-13_qn-166choice_img_no2.png
  • c)
    ch-13_qn-166choice_img_no3.png
  • d)
    ch-13_qn-166choice_img_no4.png
Q.23
A long, hollow conducting cylinder is kept coaxially inside another long, hollow conducting cylinder of larger radius. Both the cylinders are initially electrically neutral [ IIT 2007]
  • a)A potential difference appears between the two cylinders when a charge density is given to the inner cylinder
  • b) A potential difference appears between the two cylinders when a charge density is given to the outer cylinder
  • c)No potential difference appears between the two cylinders when a uniform line charge is kept along the axis of the cylinder
  • d)No potential difference appears between the two cylinders when same charge density is given to both the cylinders
Q.24
Consider a neutral conducting spher. A positive point charge is placed outside the sphere. The net charge on the sphere is then [ IIT 2007]
  • a) negative and distributed uniformly over the surface of the sphere
  • b) negativ and appers only at the point on the sphere closer to the point charge
  • c) negative and distributed non-uniformly over the entire surface of the sphere
  • d) Zero
Q.25
A spherical portion has been removed from a solid surface having a charge distributed uniformly in its volume as shown in the figure. The electric field inside the empited space is .. [ IIT 2007]
ch-13_que_no-169_img_no1.png
  • a)zero everywhere
  • b) non-zero and uniform
  • c)non-uniform
  • d)zero only at its center
Q.26
A proton is released from rest at a distance of 10-4Å from nucleus of mercury atom (Z=80). The kinetic energy of the proton when it is far away from the nucleus is
  • a) 12eV
  • b) 12 KeV
  • c) 1.2MeV
  • d) 12 MEV
Q.27
positive and negative point charges of equal magnitude are kept at (0, 0, a/2) and ( 0, 0, -a/2) respectively. the work done by the electric field when another positive point charge is moved from ( -a, 0, 0) to ( 0, a, 0) is [ IIT 2007]
  • a) positive
  • b) negative
  • c)zero
  • d)depends on the path connectingthe initial and final positions
Q.28
Consider a system of three charges q/3, q/3 and 2q/3 placed at points A, B and C resppectively, as shown in the figure. Take O to be the centre of the circle of radius R and angle CAB=660°.. [ IIT 2008]
ch-13_que_no-171_img_no1.png
  • a) The electric field at point O is q / 8πεoR2 directed along negative x-axis
  • b) the potential energy of the system is zero
  • c)the magnitude of the force between the charges at C and B is q2 / 54πεoR2
  • d)the potential at point O is q/ 12πεoR
Q.29
A parallel plate capacitor C with plates of unit area and separation d is filled with liquid of dielectric constant K=The level of liquid is d/3 initially. Suppose the liquid level decreases at a constant speed v, the time constant as a function of time t is [ IIT 2008]
ch-13_que_no-172_img_no1.png
  • a)
    ch-13_qn-172choice_img_no1.png
  • b)
    ch-13_qn-172choice_img_no2.png
  • c)
    ch-13_qn-172choice_img_no3.png
  • d)
    ch-13_qn-172choice_img_no4.png
Q.30
Theree concentric metallic spherical shell of radii R, 2R, 3R are given charges Q1, Q2 and Q3 respectively. It is found that the surface charge densities of outer surfaces of the shells are equal. Then the ratio of the charges given to the shell Q1: Q2 : Q3 is [IIT 2009]
  • a)1:2:3
  • b) 1:3:5
  • c)1:4:9
  • d)1:8:18
Q.31
A disc of radius a/4 having a uniformly distributed charge 6C is placed in the x-y plane with its centre at ( -a/2, 0, 0). A rod of length a carrying a uniformly distributioed charge 8C is placed on the x-axis from x=a/4 to x=5a/Two point charges -7C and 3C are palaced at (a/4, -a/4, 0) and (-3a/4, 3a/4, 0), respectively. Consider a cubical surface formed by six surfaces x=± a/2, y=±a/2, x=± a/The electric flux throgh this cubical surface is [ IIT 2009]
ch-13_que_no-174_img_no1.png
  • a) -2C/εo
  • b) 2C/εo
  • c) 10C/εo
  • d)12C/εo
Q.32
Eight drops of mercury of equal radii and possessing equal charges combined to form a big drop. Then the capacitance of bigger drop compared to each individual drop is [ MNR 1987]
  • a) 8 times
  • b) 4 times
  • c)2 times
  • d)32 times
Q.33
Two condensers of capacity 0.3µF and 0.6µF respectively are connected in series. The combination is connected across a potential of 6V. The ratio of energies stored by the condenser wil be [ MPPMT 1990]
  • a) 1/2
  • b) 2
  • c) 1/4
  • d) 4
Q.34
A parallel plate capacitor has a capacity C. The separation between plates is doubled and a dielectric medium is inserted between plates. The new capacitance is 3C. The dielectric constant of medium is
  • a)1.5
  • b) 3.0
  • c)6.0
  • d)12.0
Q.35
If two conducting spheres are separately charged and then brought in contact
  • a) the total energy of the two sphere is conserved
  • b) the total charge on the spheres is conservered
  • c)both the total energy and charge are conservered
  • d)the final potential is always the mean of the original potential of the two spheres
Q.36
A potential difference V is applied across two capacitors of capacitance C1 and C2 connected in series. Then the potential difference across C1 will be
  • a) VC2 / C1
  • b) V( C1 + C2) /C1
  • c)VC2 / ( C1 + C2)
  • d)VC1 / ( C1 + C2)
Q.37
Three capacitors of capacitance 3µF, 9µF and 18µF are connected in series and another time in parallel. The ratio of equivalent capacitance in the two case ( Cs / Cp) will be [ CPMT 1990]
  • a) 1:15
  • b) 15:1
  • c) 1:1
  • d) 1:3
Q.38
The electric field between the two spheres of a charged spherical condenser: [ MPPMT 1994]
  • a)is zero
  • b) is constant
  • c)increases with distance from the centre
  • d)decreses with distance from the centre
Q.39
The capacity of a parallel plate condenser is 5µF. When a glass plate is placed between the plates of the condenser, its potential difference reduces to 1/8 of the original value. The value of the dielectric constant of glass is [ MPPMT 1985]
  • a) 1.6
  • b) 8
  • c)5
  • d)40
Q.40
A glass slab is put within the plates of a charged parallel plate condenser. Which of the following quanities does not change? [ MPPMT 1998]
  • a) energy of the condenser
  • b) capacity
  • c)intensity of electric field
  • d)charge
Q.41
A 4 µF conductor is charged to 400V and then its plates are joined through a resistance of 1kΩ. The heat produced in the resistance is [ CBSE 1994]
  • a) 0.61 J
  • b) 1.28J
  • c) 0.64J
  • d) 0.32J
Q.42
An infinite number of identical capaciotrs each of capaciatance 1µF are connected as shown in figure. Then the equivalent capacitance between A and B is [ AP 1990]
ch-13_que_no-185_img_no1.png
  • a)1 µF
  • b) 2µF
  • c)1/2µF
  • d)∞
Q.43
A capacitor of capacitance 2µF is charged to a potential difference of 200 V. After disconnecting from battery, it is connected in parallel with an another uncharged capacitor. The common potential is 40V. The capacitance of the second capacitor is [ CPMT 1991]
  • a) 2µF
  • b) 4µF
  • c)8µF
  • d)16µF
Q.44
Two point charges at a certain distance experience a force of 5N. Each charge is doubled in magnitude and distance between the two is halved. The interacting force would be
  • a) 16 N
  • b) 80 N
  • c)5 N
  • d)20 N
Q.45
Four metallic plates each with a surface area of one side A, are palced at a distance d from each other. The plates are connected as shown in the figure. Then the capacitance of the system between a and b is :
ch-13_que_no-187_img_no1.png
  • a)3εoA / d
  • b) 2εoA / d
  • c)2εoA / 3d
  • d)3εoA / 2d
Q.46
Two parallel plates, separated by a distance of 5mm, are kept at a potential difference of 50V. A particle of mass 10-15kg and charge 10-11 C enters in it with a velocity 107 m/s. The acceleration of the particle will be [ MPPMT 1997]
  • a) 108 m/s2
  • b) 5 ×105 m/s2
  • c) 105 m/s2
  • d) 2 × 103 m/s2
Q.47
Pulling the plates of charged capacitor apart
  • a)increases the capacitance
  • b) increases the potential difference
  • c)does not affect potential difference
  • d)decreases the potential difference
Q.48
N identical spherical drop charged to same potential V are combined to form the big drop will be [ JIPMER 1998]
  • a) V
  • b) V×N
  • c)V/N
  • d)V ×N2/3
Q.49
The plates of a parallel plate capacitor are charged up to 100V. A 2mm thick plate is inserted between the plates, then to maintain the same potential difference, the distance between the capacitor plates is increased by 1.6 mm. The dielectric constant of the plates is [ MPPMT 1991]
  • a) 5
  • b) 1.25
  • c)4
  • d)2.5
Q.50
Four equal capacitors, each with a capacitance C are connected to a battery of e.m.f 10V as shown in figure. The midpont of the capacitor system is connected to earth. Then the potentials of B and D are respectively
ch-13_que_no-192_img_no1.png
  • a) +10V, zero voly
  • b) +5V , -5V
  • c) -5V, +5V
  • d) zero volt, 10 volt
0 h : 0 m : 1 s