Q.1
Two charges 4q and q are placed 30cm apart. At what point the value of electric field will be zero
  • a) 10 cm away from and between the charges
  • b) 20 cm away from q and between the charge
  • c)10 cm away from q and outside the line joining the charge
  • d)10 cm away from 4q and out side the line joining them
Q.2
If Q=2 C and force on it is F=10 N. Then the value of field intensity will be
  • a) 100 N/C
  • b) 50 N/C
  • c) 200 N/C
  • d) 10 N/C
Q.3
Two similar charges 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
ch-13_que_no-399_img_no1.png
  • a) it is moved towards A
  • b) it is moved towards B
  • c)it is moved upwards AB
  • d)distance between A and B is reduced
Q.4
A thin metal plate P is inserted between the plates of a parallel -plate capacitor of capacitance C in such a way that its edges touches the two plates. The capacitance now becomes
ch-13_que_no-400_img_no1.png
  • a) C/2
  • b) 2C
  • c) 0
  • d) ∞
Q.5
An accelerated or decelerated charges produces
  • a)electric field only
  • b) magnetic field only
  • c)localised electric and magnetic fields
  • d)A stationary charge produces both electric and magnetic fields
Q.6
Two point charges is air at a distance of 20 cm from each other interact with a certain force. At what distance from each other should these charges be placed in oil of relative permitivity 5 to obtain the same force of interaction
  • a) 8.94×10-2 m
  • b) 0.894×10-2 m
  • c)89.4×10-2 m
  • d)8.94×102 m
Q.7
The force between two point charges placed in vacuum is 18N at separation of 1mm. If a glass plate of thickness 1mm and dielectric constant 6 be kept between the charges then the force between them would be
  • a) 18 N
  • b) 108N
  • c)3 N
  • d)3×10-6N
Q.8
A pendulum bob of mass 80mg and carrying a charge of 2×10-8 C is at rest in a horizontal uniform electric field of 20,000 N/m. Find the tension in the thread of pendulum
  • a) 8.8 × 10-2 N
  • b) 8.8 × 10-3 N
  • c) 8.8 × 10-4 N
  • d) 8.8 × 10-5 N
Q.9
Six charges +Q each are placed at the corners of a regular hexagon of side 'a', the electric field at the centre of hexagon is
  • a)zero
  • b) 6KQ2 / a2
  • c)KQ2 / a2
  • d)6KQ2 / (√2×a2)
Q.10
Two charged sphere A and B are charged with the charges of +10 C and +20 C respectively and separated by a distance of 80 cm. The electric field at a point on the line joining the center of the two spheres will be zero at a distance from sphere A..
  • a) 20 cm
  • b) 33 cm
  • c)55 cm
  • d)60 cm
Q.11
The electric field inside a spherical shell of uniform surface charge density is
  • a) zero
  • b) constant, but non zero
  • c)proportional to the distance from centre
  • d)non of the above
Q.12
If the electric field is uniform, then the electric lines of forces are
  • a) Divergent
  • b) Convergent
  • c) Circular
  • d) Parallel
Q.13
Electric lines of forces
  • a)Exists everywhere
  • b) Are imaginary
  • c)Exist only in the immediate vicinity of electric charges
  • d)None of the above
Q.14
Charge reside on the
  • a) Outer surface of the charged conductor
  • b) Inner surface of charged conductor
  • c)Inner as well as outer surface of the charged conductor
  • d)None of the above
Q.15
In an electric field the work done in moving a unit positive charge between two points is the measure of
  • a) Resistance
  • b) Potential difference
  • c) Intensity of electric field
  • d)Capacitance
Q.16
A ring of radius R carries a uniformly distributed charge +Q . A point charge -q is placed on the axis of the ring at a distance 2R from the centre of the ring and released from rest. The particle
  • a) BEcomes in rest condition immediately
  • b) Execute simple harmonic motion
  • c) Motion is not SHM
  • d) come at the centre of the ring immediately
Q.17
The ratio of the electric field due to an electric dipole on its axis and on the perpendicular bisector of the dipole is
  • a)1:2
  • b) 2:1
  • c)1:4
  • d)4:1
Q.18
Which of the following charge is not possible
  • a) 1.6×10-18C
  • b) 1.6×10-19C
  • c)1.6×10-20C
  • d)None of these
Q.19
A point charge q1 exerts a force F on qAn equal charge q3 is now kept near qThe resultant force on q2 due to q1 will be
  • a)F
  • b)2F
  • c)F/2
  • d)-F
Q.20
Two charged spheres of radius R are kept at a distance d ( d >2R). One has a charge +q and other -q. The force between them will be
ch-13_que_no-416_img_no1.png
  • a) KQ2 / d2
  • b) > KQ2 / d2
  • c) < KQ2 / d2
  • d) None of these
Q.21
A metal sphere us placed in an uniform electric field which one is a correct electric line of force
ch-13_que_no-417_img_no1.png
  • a)1
  • b) 2
  • c)3
  • d)4
Q.22
A charged particle is free to move in electric field will it always move along the electric field lines of force
  • a) yes, always
  • b) some times
  • c)never
  • d)no, if V is inclined to field
Q.23
What will be the change in potential energy of q3, in moving it along CD for the following figure q1=q2=40nC and q3=20nC
ch-13_que_no-419_img_no1.png
  • a)3 ×10-7 J
  • b) -3 ×10-7 J
  • c)2.88 ×10-7 J
  • d)1.88 ×10-3 J
Q.24
In following figure, where the charge q must be kept, so that the potential energy of the system will be minimum
ch-13_que_no-420_img_no1.png
  • a) x=1 cm
  • b) x=4 cm
  • c) x=3 cm
  • d) x=2 cm
Q.25
The charges of 10µC each are kept at three corners of an equilateral triangle of 10cm side. What is the potential energy of system?
  • a)27 J
  • b) -27J
  • c)20J
  • d)0 J
Q.26
A electron ( mass m, charge e) is accelerated through a potential difference of V volts. Find the final velocity of electrons
  • a) v=√ (2eV/m)
  • b) v=√(eV/m)
  • c)v=√(m/eV)
  • d)v=√(m/2eV)
Q.27
Three charges 2q, -q, -q are located at the vertices of an equilateral triangle. At the circumcentre of the triangle
  • a) The field is zero but potential is not zero
  • b) The field is non-zero but the potential is zero
  • c)Both, field and potential are zero
  • d)Both, field and potential are non-zero
Q.28
A proton is released from rest towards an another proton with a velocity of 7.45×105 m/s. The minimum approach is
  • a) 10-12 m
  • b) 10-14 m
  • c) 10-10 m
  • d) 10-8 m
Q.29
A particle of mass 6µg carrying a charge of 10-9C is placed in the electric field of strength E = 6×105 V/m, the acceleration acquired by the particle is
  • a) 102 m/sec2
  • b) 105 m/sec2
  • c) 103 m/sec2
  • d) 1020 m/sec2
Q.30
Two small balls having equal positive charge Q on each are suspended by two insulating strings at equal length L meter, from a hook fixed to stand. The whole set up is taken in a satellite into space where there is no gravity. Then the angle θ between two strings and tension in each string is
  • a) 0, K(q/L)2
  • b) π,(K/2)(q/L)2
  • c) π,(K/4)(q/L)2
  • d) π/2, (K/2)(q/L)2
Q.31
Three charges -q1, +q2, -q3 are placed as shown in figure. The x -componant of force on -q1 is proportional to
ch-13_que_no-427_img_no1.png
  • a)
    ch-13_qn-427choice_img_no1.png
  • b)
    ch-13_qn-427choice_img_no2.png
  • c)
    ch-13_qn-427choice_img_no3.png
  • d)
    ch-13_qn-427choice_img_no4.png
Q.32
there is an electric field E in X direction. IF the work done on moving a charge 0.2C through a distance of 2m along a line making an angle 60° with the x-axis is 4.0, what is the value of E
  • a)√3 N/C
  • b) 4 N/C
  • c)5 N/C
  • d)none of these
Q.33
The electric field at a point on equatorial line of a 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
Q.34
Two identical small balls each of mass, are suspended by two light inelastic conducting threads each of length l from the same fixed point support. If the distance (d) between two balls is very less the d is equal to
  • a)
    ch-13_qn-428choice_img_no1.png
  • b)
    ch-13_qn-428choice_img_no2.png
  • c)
    ch-13_qn-428choice_img_no3.png
  • d) none oth these
Q.35
A metal sphere A of radius R has a charge of Q on it. The field at point B outside the sphere is E. Now another sphere of radius R having a charge -Q is placed at point B. The total field at a point midway between A and B due to both sphere is
  • a)4E
  • b) 8E
  • c)12E
  • d)16E
Q.36
A uniformly charged rod with charge per unit length λ is bent in to the shape of a semicircle of radius R. The electric field at the centre is
  • a) 2Kλ / R
  • b) Kλ / 2R
  • c)Zero
  • d)None
Q.37
A cylinder of radius R and length L is placed in a uniform electric field E parallel to the axis of cylinder, the total flux for the surface of the cylinder is given by
  • a) 2πR2E
  • b) πR2 / E
  • c)2πR2 / E
  • d)zero
Q.38
Electric potential in an electric field is given by V=K/r ( K being constant), if position vector r=2i+3j +6k then electric field will be
  • a)
    ch-13_qn-432choice_img_no1.png
  • b)
    ch-13_qn-432choice_img_no2.png
  • c)
    ch-13_qn-432choice_img_no3.png
  • d)
    ch-13_qn-432choice_img_no4.png
Q.39
The electric field at the surface of a charged spherical conductor is 10kV/m. The electric field at a distance equal to the diameter from the centre will be
  • a)2.5 V/m
  • b) 2.5 kV/m
  • c)5.0 kV/m
  • d)5.0V/,
Q.40
Potential difference between centre and the surface of a sphere of radius R with uniform charge density σ with in it will be
  • a) σR2 /6εo
  • b) σR2 /4εo
  • c)zero
  • d)σR2 /2εo
Q.41
Two parallel plates of infinite dimensions are uniformly charged. The surface charge density on one is σA while on the other is σB field intensity at point C will be
  • a) proportional to (σA - σB)
  • b) proportional to (σA + σB)
  • c)zero
  • d)non-zero
Q.42
Two charged metal plates each of area (A) carry charge +q and -q and face each other, the plates are separated by a small distance (d) the electric field between plates would be
  • a) 2q/εoA
  • b) 2qA/εoA
  • c) q/εoA
  • d) A/qεo
Q.43
An electron is situated 3×10-9 m from one α-particle and 4×10-9m from another α particle. The magnitude of force on electron, when two α particles are 5 ×10-9 m apart is
  • a)5.64×10-11 N
  • b) 56.4×10-11 N
  • c)0.564×10-11N
  • d)564×10-11 N
Q.44
Two conducing spheres of radius a and b are equally charged. The ratio of their potential is
  • a) a2 / b2
  • b) b2 / a2
  • c)a/b
  • d)b/a
Q.45
Two similar rings P and Q ( radius 0.1 m ) are placed co-axially at a distance 0.5 m apart. The charge on P and Q is 2µC and 4µC respectively. Work done due to moving of a 5µC charge from Centre of P to the Centre of Q is
  • a) 1.28J
  • b)0.72J
  • c)0.144J
  • d)1.44J
Q.46
Three point charges -q, +Q, -q are placed along a straight line at equal distances ( say r meter) Electric potential energy of the system of charges will be
  • a) -3Kq2 / r
  • b) -8Kq2 / r
  • c) -3Kq2 / 2r
  • d) -Kq2 / 2r
Q.47
Four equal charges q are placed at corners of a square of side a. Potential energy of the whole system is
  • a)4Kq2 / a
    ch-13_qn-441choice_img_no2.png
  • b)
    ch-13_qn-441choice_img_no3.png
  • c)
    ch-13_qn-441choice_img_no4.png
  • d)
Q.48
n small drops of the same size are charged to V voltage each. If they collapse to form a single large drop, then its potential will be
  • a) V/n
  • b) Vn
  • c)Vn1/3
  • d)Vn2/3
Q.49
For the equilibrium of a charged bubble of surface tension T and radius r, the charge on the bubble should be
  • a)
    ch-13_qn-443choice_img_no1.png
  • b)
    ch-13_qn-443choice_img_no2.png
  • c)
    ch-13_qn-443choice_img_no3.png
  • d)
    ch-13_qn-443choice_img_no4.png
Q.50
An electric dipole when placed in uniform electric field E will have minimum potential energy. If the positive direction of dipole moment makes an angle with E is
  • a) π
  • b) π/2
  • c) zero
  • d) 3π/2
0 h : 0 m : 1 s