Q.1
If two conducting spheres are separately charged and then brought in contact ---
  • a) the total energy of the two spheres is conserved
  • b) the total charge on the two spheres is conserved
  • c) both the total energy and charge are conserved
  • d) the final potential is always the mean of the potential of the two spheres
Q.2
A parallel plate capacitor is charged and then disconnected from the battery. If the plates of the capacitor are then moved away from each other by the use of insulated handel, then there is increase in
  • a)the charge on either plate
  • b) the capacitance of the capacitor
  • c)voltage across the capacitor
  • d)all the above three
Q.3
Two identical air filled parallel capacitors are charged to the same potential in the manner shown in figure by closing the switch S. If now the switch is opened and the space between the plates if filled with a dielectric of relative permitivity εr then
ch-13_que_no-276_img_no1.png
  • a) the p.d across A remains constant and the charge on B remains unchanged
  • b) the p.d. across B remains constant while the charge on A remains unchanged
  • c)the p.d. as well as charge on each capacitor goes up by a factor εr
  • d)the p.d as well as the charge on each capacitor down up by a factor εr
Q.4
What physical quantity may X and Y represent? ( Y represent first mentioned quantity)
ch-13_que_no-277_img_no1.png
  • a)pressure v/s temperature of given gas at constant volume
  • b) kinetic energy v/s velocity of particle
  • c)capacitance v/s charge to given constant potential
  • d)potential v/s capacitance to given constant charge
Q.5
A number of capacitors, each of capacitance 1µF and each one of which gets punctured if a potential difference just exceeding 500V is applied, are provided. Then an arrangement suitable for giving a capacitor of capacitance 3µF across which 2000V may be applied requires at least
  • a)4 component capacitor
  • b) 12 component capacitor
  • c)48 component capacitor
  • d)3 component capacitor
Q.6
Three capacitors, with capacitance of 1µF, 2µF, 3µF, are connected in series. Each capacitor gets punctured if potential difference just exceeding 100 volt is applied. If the group is connected across a 300 Volt circuit then the capacitor most likely to puncture first is
  • a) of capacitance 1µF
  • b) of capacitance 2µF
  • c)of capacitance 3µF
  • d)of capacitance either 1µF, 2µF, 3µF
Q.7
A slab X is placed between the two parallel isolated charged plates, as shown. IF Ep and Eq denotes the intensity of electric field at P and Q
ch-13_que_no-283_img_no1.png
  • a) Ep is reduced by the presence of X if X is metallic
  • b) Eq is increased by the presence of X if X is dielectric
  • c)Eq is in opposite sense to Ep if X is a dielectric
  • d)Eq is zero if X is metallic
Q.8
Two spherical conductors of capacitances 3.0pF and 5.0pF are charged to potentials of 300V and 500V. The two are connected resulting in redistribution of charges. Then the final potential is
  • a) 300 V
  • b) 500 V
  • c) 425 V
  • d) 400 V
Q.9
A battery of e.m.f V volts, resistors R1 and R2, a condenser C and switches S1 and S2 are connected in a circuit as shown in the figure below. The condenser will get fully charged to V volts when
ch-13_que_no-285_img_no1.png
  • a)S1 and S2 are both closed
  • b) S1 and S2 are both open
  • c)S1 is open and S2 is closed
  • d)S1 is closed and S2 is open
Q.10
The amount of work done in increasing the voltage across the plates of a capacitor from 5V to 10V is W. The work done in increasing it from 10V to 15V will be
  • a) 0.6W
  • b) W
  • c)1.25W
  • d)1.67W
Q.11
A parallel plate capacitor is charged to 100volts and then connected to an identical capacitor in aparallel. The second capacitor has some dielectric between its plates. If the common potential is 20V then the dielectric constant of the dielectric is
  • a) 2.5
  • b) 4
  • c) 5
  • d) 8
Q.12
The electric field midway between two charges 0.1µC and 0.4µC separated by a distance of 60cm is
  • a) 5 ×103 N/C
  • b) 9 ×104 N/C
  • c)5 ×104 N/C
  • d)3 ×104 N/C
Q.13
Two identical parallel plate capacitors are connected in series and connected to a constant voltage source of Vo Volt. If one of the capacitors is completely immersed in a liquid of dielectric constant K, the potential difference between the plates of the other capacitor change to
  • a)
    ch-13_qn-289choice_img_no1.png
  • b)
    ch-13_qn-289choice_img_no2.png
  • c)
    ch-13_qn-289choice_img_no3.png
  • d)
    ch-13_qn-289choice_img_no4.png
Q.14
A parallel plate capacitor is filled by a dielectric whose permitivity varies with applied voltage according to relation εr=αV where α=1 volt-The same capacitor containing no dielectric charged to a voltage of 72 V is connected parallel to the first non liner uncharged capacitor. The final voltage across capacitor is
  • a) 19V
  • b) 6V
  • c)36V
  • d)8V
Q.15
In a circuit diagram potential difference between points A and B is 200 volts, the potential difference between a and b when the switch S is open is
ch-13_que_no-291_img_no1.png
  • a) 100 V
  • b) (200/3) V
  • c)(100/3)V
  • d)50 V
Q.16
Five identical capacitor plates, each of area A , are arranged such that the adjacent plates are at a distance d apart. The plates are connected to battery of e.m.f E volts as shown
ch-13_que_no-292_img_no1.png
  • a)
    ch-13_qn-292choice_img_no1.png
  • b)
    ch-13_qn-292choice_img_no2.png
  • c)
    ch-13_qn-292choice_img_no3.png
  • d)
    ch-13_qn-292choice_img_no4.png
Q.17
Three uncharged capacitors of capacitance C1, C2 and C3 are connected as shown in figure to one another and to point A, B, and D at potentials VA , VB , VD . then the potential at O will be
ch-13_que_no-293_img_no1.png
  • a)
    ch-13_qn-293choice_img_no1.png
  • b)
    ch-13_qn-293choice_img_no2.png
  • c)
    ch-13_qn-293choice_img_no3.png
  • d)
    ch-13_qn-293choice_img_no4.png
Q.18
The Gaussian surface for calculating the electric field due to a charge distribution is
  • a) any closed surface around the charge distribution
  • b) any surface near the charge distribution
  • c)a spherical surface
  • d)a symmetrical closed surface at every point of which electric field has a single fixed value
Q.19
Three capacitors of capacitance 4µF, 6µF and 12µF are connected first in series and then in parallel. What is the ratio of equivalent capacitance in the two cases?
  • a) 2:3
  • b) 1:11
  • c)11:1
  • d)1:3
Q.20
A parallel plate capacitor has a capacitance of 50pf in air and 105pf when immersed in oil. The dielectric constant of the oil is
  • a) 50/105
  • b) 1
  • c) 2.1
  • d) ∞
Q.21
When a capacitor is connected to a battery
  • a)an alternating current flows in the circuit
  • b) no current flows at all
  • c)a current flows for some time and finally decreases to zero
  • d)current keeps on increasing and reaches maximum after some time
Q.22
When a charge q is moved once round a circle of radius R with charge Q at the centre of the circle, work done is
  • a) zero
  • b) Qq / 4πεoR
  • c)Qq / 4πεoR2
  • d)Qq /R
Q.23
A work of 100 J is performed in carrying a charge of -5C from infinity to a particular point in an electrostatic field. The potential of this point is
  • a) 100V
  • b) 5V
  • c)-20V
  • d)20V
Q.24
Two copper spheres A and B of same size are charged to some potential. A is hollow and B is solid. Which of the two holds more charge>
  • a) Solid sphere cannot hold any charge
  • b) Hollow sphere can not hold any charge
  • c) Both have zero charge
  • d) Both have same charge
Q.25
An electron initially at rest is accelerated through a P.D. of one volt. The energy acquired by electrons is
  • a) 1 J
  • b) 1.6×10⁻¹⁹ J
  • c)10-19 J
  • d)1.6×10⁻¹⁹ erg
Q.26
The S.I. unit of surface integral of electric field is
  • a) NC-1
  • b) Nm2C
  • c)J/C
  • d)V/m
Q.27
A bird sitting on a high power line
  • a) gets killed instantly
  • b) gets a mild shock
  • c) is not affected practically
  • d) gets a fatal shock
Q.28
The mutual interaction between two charged bodies is best understood in terms of
  • a) the action at a distance view
  • b) the field concept
  • c)a material connection between the charges
  • d)medium in between the charges
Q.29
Torque on a dipole in an electric field is maximum when angle between p and E is
  • a) 0°
  • b) 90°
  • c)45°
  • d)180°
Q.30
When an electric dipole is placed in a uniform electric field, it experiences
  • a) a force as well as torque
  • b) a torque but not force
  • c) a force but not torque
  • d) neither for nor torque
Q.31
The value of a charge q at the centre of two equal and like charges Q so that the three charges are in equilibrium [ kerala P.M.T 2004]
  • a)-Q/4
  • b) +Q/4
  • c)Q
  • d)Q/2
Q.32
A charged spherical shell does not produce an electric field at any [ kerala P.M.T. 2004]
  • a) interior point
  • b) outer point
  • c)beyond 2 meters
  • d)beyond 10 meters
Q.33
The charge on 4µF capacitor in the given circuit is
ch-13_que_no-311_img_no1.png
  • a)12 µF
  • b) 24 µF
  • c)36 µF
  • d)32 µF
Q.34
Two equal metal balls are charged to 10 and -20 units of electricity. Then they are brought in contact with each other and then are brought in to original distance. The ratio of magnitudes of force between the two balls before and after contact is [ Kerala P.M.T 2004]
  • a) 8:1
  • b) 1:8
  • c) 1:2
  • d) 2:1
Q.35
A conductor having a cavity is given a positive charge. Then field strengths EA, EB and EC at points A ( with in cavity) at B (within conductor) and C ( outside conductor) will e [ kerala P.M.T 2004]
  • a)EA=0, EB=0, EC=0
  • b) EA=0, EB=0, EC ≠=0
  • c)EA ≠=0, EB=0, EC≠=0
  • d)EA ≠=0, EB≠=0 , EC≠=0
Q.36
The potential at point P, which is forming a corner of a square of side 93mm with charges Q1=33 nC, Q2 -51 nC, Q3=47nC located at the other three corners is nearly [ kerala P.E.T 2004]
  • a) 16 kV
  • b) 4 kV
  • c)400 V
  • d)160 V
Q.37
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 between capacitor plates, the distance between the capacitor plate is increased by 1.6 mm. The dielectric constant of the plate is
  • a)5
  • b) 1.25
  • c)4
  • d)2.5
Q.38
If one penetrates a uniformly charged spherical shell, the electric field strength E
  • a) increases
  • b) decreases
  • c)remains same as surface
  • d)is zero at all points
Q.39
Two small spheres, each carrying a charge q, placed r meters apart, repel each other with a force F. If one of the spheres is taken around the other one in a circular path of radius r, the work done will be
  • a) F × r
  • b) F × 2πr
  • c)F / 2πr
  • d)zero
Q.40
An electric dipole consists of two opposite charges each of magnitude 1.0µC separated by a distance of 2.0cm. The dipole is placed in an external field of 1.0×105 N/C. The max. torque on the dipole is
  • a) 0.2×10⁻³ N-m
  • b) 1.0×10⁻³ N-m
  • c) 2.0×10⁻³ N-m
  • d) 4.0×10⁻³ N-m
Q.41
A positively charged sphere hangs from a silk thread. We put a positive test charge qo at a point and measure F/qo then it can be predicted that the electric field strength E is
  • a) > F/qo
  • b)=F/qo
  • c)< F/qo
  • d)can not be estimated
Q.42
Hollow metal sphere of radius 5 cm is charged such that the potential on its surface is 10V. The potential at a distance of 2cm from the centre of the sphere is
  • a) zero
  • b) 10 V
  • c) 4 V
  • d) 10/3 V
Q.43
Particle A has charge +Q and particle B has charge +4Q with each of them having the same mass. When allowed to fall from rest through same electrical potential difference, ratio of their speed VA / VB will become
  • a)2:1
  • b) 1:2
  • c)1:4
  • d)4:1
Q.44
Which of the following is a volt
  • a) erg per cm
  • b) joule per coulomb
  • c) erg per ampere
  • d) newton/(coulomb×metre2)
Q.45
The capacitance of an isolated conducting sphere of radius R is proportional to
  • a) R2
  • b)1 / R2
  • c)1 /R
  • d)R
Q.46
A condenser is connected across another charged condenser. The energy in the two condenser will
  • a) Be equal to the energy in the initial condenser
  • b) Be less than that in the initial condenser
  • c) Be more than that in the initial condenser
  • d) BE more or less depending on the relative capacitances of the two condenser
Q.47
Work done in moving a unit positive charge through a distance of x meter on an equipotential surface is [ Panjab C.E.T 1997]
  • a)x joule
  • b) (1/x) joule
  • c)zero
  • d)x2 joule
Q.48
If a positive charge is shifted from lower potential to region of higher potential region, the electric potential energy
  • a) decreases
  • b) increases
  • c)remains same
  • d)may increase / decrease
Q.49
If the flux of electric field through a closed surface is zero
  • a) electric field must be zero everywhere on the surface
  • b) electric field may be zero everywhere on the surface
  • c)charge in the vicinity of the surface must be zero
  • d)charge inside the surface must be zero
Q.50
The electric potential V at any point x, y, z ( all in meters) in space is given by V=4x2 volt. The electric field at the point (1m, 0, 2m) in volt/meter is
  • a) 8 V/m along negative X -axis
  • b) 8 V/m along positive X -axis
  • c) 16 V/m along negative X axis
  • d) 16 V/m along positive Z axis
0 h : 0 m : 1 s