JEE Questions for Physics Electrostatics I Quiz 7 - MCQExams.com

Two charged spheres separated at a distance d exert a force F on each other. If they are immersed in a liquid of dielectric constant 2, then what is the force (if all conditions are same)
  • F/2
  • F
  • 2F
  • 4F
When 1019 electrons are removed from a neutral metal plate, the electric charge on it is
  • –1.6 C
  • +1.6 C
  • 10+19 C
  • 10–19 C
Electric charges of 1µC,–1 µC and 2µC are placed in air at the corners A, B and C respectively of an equilateral triangle ABC having length each side 10 cm. The resultant force on the charge at C is
  • 0.9 N
  • 1.8 N
  • 2.7 N
  • 3.6 N
Charge on α–particle is
  • 4.8 × 10–19C
  • 1.6 × 10–19C
  • 3.2 × 10–19C
  • 6.4 × 10–19C
Two charges are at a distance `d\' apart. If a copper plate (conducting medium) of thickness d/2 is placed between them, the effective force will be
  • 2F
  • F/2
  • 0

  • Physics-Electrostatics I-70755.png
Two electrons are separated by a distance of 1Å. What is the coulomb force between them
  • 2.3 × 10–8 N
  • 4.6 × 10–8 N
  • 1.5 × 10–8 N
  • None of these
Two copper balls, each weighting 10 g are kept in air 10 cm apart. If one electron from every 106 atoms is transferred from one ball to the other, the coulomb force between them is (atomic weight of copper is 63.5)
  • 2.0 × 1010N
  • 2.0 × 104N
  • 2.0 × 108N
  • 2.0 × 106N
A solid conducting sphere of radius a has a net positive charge 2Q. A conducting spherical shell of inner radius b and outer radius c is concentric with the solid sphere and has a net charge –Q. The surface charge density on the inner and outer surfaces of the spherical shell will be
Physics-Electrostatics I-70758.png

  • Physics-Electrostatics I-70759.png
  • 2)
    Physics-Electrostatics I-70760.png

  • Physics-Electrostatics I-70761.png
  • None of the above
Two charges placed in air repel each other by a force of 10–4 N. When oil is introduced between the charges, the force becomes 2.5 × 10–5N. The dielectric constant of oil is
  • 2.5
  • 0.25
  • 2.0
  • 4.0
Two particle of equal mass m and charge q are placed at a distance of 16 cm. They do not experience any force. The value of is q/m is
  • 1
  • 2)
    Physics-Electrostatics I-70764.png

  • Physics-Electrostatics I-70765.png

  • Physics-Electrostatics I-70766.png
When a glass rod is rubbed with silk, it
  • Gains electrons from silk
  • Gives electrons to silk
  • Gains protons from silk
  • Gives protons to silk
Dielectric constant for metal is
  • Zero
  • Infinite
  • 1
  • Greater than 1
A charge of Q coulomb is placed on a solid piece of metal of irregular shape. The charge will distribute itself
  • Uniformly in the metal object
  • Uniformly on the surface on the object
  • Such that the potential energy of the system is minimized
  • Such that the total heat loss is minimized
Two identical conductors of copper and aluminum are placed in an identical electric fields. The magnitude of induced charge in the aluminum will be
  • Zero
  • Greater than in copper
  • Equal to that in copper
  • Less than in copper
Two spherical conductors B and C having equal radii and carrying equal charges in them repel each other with a force F when kept apart at some distance. A third spherical conductor having same radius as that of B but uncharged is brought in contact with B but uncharged is brought in contact with B, then brought in contact with C and finally removed away from both. The new force of repulsion between B and C is
  • F/4
  • 3F/4
  • F/8
  • 3F/8
When a body is earth connected, electrons from the earth flow into the body. This means the body is
  • Unchanged
  • Charged positively
  • Charged negatively
  • An insulator
The charges on two spheres are +7µC and – 5µC respectively. They experience a force F. If each of them is given and additional charge of –2µC, the new force of attraction will be
  • F
  • F/2

  • Physics-Electrostatics I-70771.png
  • 2F
Two equally charged, identical metal spheres A and B repel each other with a force \'F\' The spheres are kept fixed with a distance ‘r’ between them. A third identical, but uncharged sphere C is brought in contact with A and then placed at the mid-point of the line joining A and B. The magnitude of the net electric force on C is
  • F
  • 3F/4
  • F/2
  • F/4
Two charges of equal magnitudes and at a distance r exert a force F on each other. If the charges are halved and distance between them is doubled, then the new force acting on each charge is
  • F/8
  • F/4
  • 4F
  • F/16
An infinite number of charges, each of charge 1µC, are placed on the x-axis with co-ordinates x = 1, 2, 4, 8, ...... ∞. If a charge of 1C is kept at the origin, then what is the net force acting on 1C charge
  • 9000 N
  • 12000 N
  • 24000 N
  • 36000 N
The top of the atmosphere is at about 400 kV with respect to the surface of the earth, corresponding to an electric field that decreases with altitude. Near the surface of the earth, the field is about 100 Vm–1. Still, we do not get an electric shock as we step out of our house into the open house because (assume the house to be a steel cage so that there is no field inside)
  • There is a potential difference between our body and the ground
  • 100 Vm–1 is not a high electric field so that we do not feel the shock
  • Our body and the ground forms an equipotential surface
  • The atmosphere is not a conductor
Four metal conductors having different shapes
1. A sphere
2. Cylindrical
3. Pear
4. Lightning conductor
are mounted on insulating stands and charged. The one which is best suited to retain the charges for a longer time is
  • 1
  • 2
  • 3
  • 4
Identify the wrong statement in the following. Coulomb\'s law correctly describes the electric force that
  • Binds the electrons of an atom to its nucleus
  • Binds the protons and neutrons in the nucleus of an atom
  • Binds atoms together to form molecules
  • Binds atoms and molecules together to form solids
Which of the following will represent Coulomb\'s law?

  • Physics-Electrostatics I-70776.png
  • 2)
    Physics-Electrostatics I-70777.png

  • Physics-Electrostatics I-70778.png

  • Physics-Electrostatics I-70779.png
A comb run through one\'s dry hair attracts small bits of paper. This is due to
  • Comb is a good conductor
  • Paper is a good conductor
  • The atoms in the paper get polarized by the charged comb
  • The comb possesses magnetic properties
Two charges +6µC and + 15µC are placed along the x-axis at x = 0 and x = 2m respectively. A negative charge is placed between them such that the resultant force on it is zero. The negative charge is placed at
  • x = 0.775 m
  • x = 1.2 m
  • x = 0.5 m
  • Position depends on the amount of charge
Two protons are a distance of 1 × 10–10cm from each other. The forces acting on them are
  • Nuclear force and coulomb force
  • Nuclear force and gravitational force
  • Coulomb force and gravitational force
  • Nuclear, coulomb and gravitational force
Two identical conducting balls A and B have positive charges q1 and q2 respectively. But q1 ≠ q2. The balls are brought together so that they touch each other and then kept in their original positions. The force between them is
  • Less than that before the balls touched
  • Greater than that before the balls touched
  • Same as that before the balls touched
  • Zero
Two small spheres of masses M1. and M2 are suspended by weightless insulating threads of lengths L1 and L2. The spheres carry charges Q1 and Q2 respectively. The spheres are suspended such that they are in level with one another and the threads are inclined to the vertical at angles of θ1 and θ2 as shown. Which one of the following conditions is essential, if θ1= θ2
Physics-Electrostatics I-70782.png
  • M1 ≠ M2 but Q1 = Q2
  • M1 = M2
  • Q1 = Q2
  • L1 = L2
A ball with charge –50 e is placed at the centre of a hollow spherical shell which has a net charge of –50 e. What is the charge on the shell\'s outer surface?
  • –50 e
  • Zero
  • –100 e
  • +100 e
Two charged spherical conductors of radii R1. and R2 are connected by a wire. Then, the ratio of surface charge densities of the spheres σ1/ σ2 is

  • Physics-Electrostatics I-70785.png
  • 2)
    Physics-Electrostatics I-70786.png

  • Physics-Electrostatics I-70787.png

  • Physics-Electrostatics I-70788.png
A conductor has been given a charge –3 × 10–7 C by transferring electron. Mass increase (in kg) of the conductor and the number of electrons added to the conductor are respectively
  • 2 × 10–16 and 2 × 1031
  • 5 × 10–31 and 5 × 1019
  • 3 × 10–19 and 9 × 1016
  • 2 × 10–18 and 2 × 1012
A ring of radius r carries a charge Q uniformly distributed over its length. A charge q is placed at its centre will experience a force equal to

  • Physics-Electrostatics I-70791.png
  • 2)
    Physics-Electrostatics I-70792.png
  • Zero
  • None of these

Physics-Electrostatics I-70794.png
  • 0
  • 2)
    Physics-Electrostatics I-70795.png

  • Physics-Electrostatics I-70796.png

  • Physics-Electrostatics I-70797.png
Two points P and Q are maintained at the potentials of 10 V and –4V respectively. The work done in moving 100 electrons from P to Q is
  • –9.60 × 10–17 J
  • 9.60 × 10–17 J
  • –2.24 × 10–16 J
  • 2.24 × 10–16 J
Two charged spheres of radii 10 cm and 15 cm are connected by a thin wire. No charge will flow, if they have
  • The same charge on each
  • The same potential
  • The same energy
  • The same field on their surfaces
The electric field inside a spherical shell of uniform surface charge density is
  • Zero
  • Constant, less than zero
  • Directly proportional to the distance from the centre
  • None of the above
Electric lines of force about negative point charge are
  • Circular, anticlockwise
  • Circular, clockwise
  • Radial, inward
  • Radial, outward

Physics-Electrostatics I-70801.png

  • Physics-Electrostatics I-70802.png
  • 2)
    Physics-Electrostatics I-70803.png

  • Physics-Electrostatics I-70804.png
  • 900 volt
A uniform electric field having a magnitude E0 and direction along the positive X-axis exists. If the potential V is zero at x = 0, then its value at X = +x will be
  • Vx = +xE0
  • Vx = –xE0
  • Vx = +x2E0
  • Vx = –x2E0
Three charges 2q, – q, – q are located at the vertices of an equilateral triangle. At the centre of the triangle
  • The field is zero but potential is non-zero
  • The field is non-zero but potential is zero
  • Both field and potential are zero
  • Both field and potential are non-zero
Figure shows the electric lines of force emerging from a charged body. If the electric field at A and B areEA and EB respectively and if the displacement between A and B is r, then
Physics-Electrostatics I-70808.png

  • Physics-Electrostatics I-70809.png
  • 2)
    Physics-Electrostatics I-70810.png

  • Physics-Electrostatics I-70811.png

  • Physics-Electrostatics I-70812.png
In the electric field of a point charge q, a certain charge is carried from point A to B, C, D and E. Then, the work done
Physics-Electrostatics I-70813.png
  • Is least along the path AB
  • Is least along the path AD
  • Is zero along all the paths AB, AC, AD and AE
  • Is least along AE
An electron and a proton are in a uniform electric field, the ratio of their accelerations will be
  • Zero
  • Unity
  • The ratio of the masses of proton and electron
  • The ratio of the masses of electron and proton
Two parallel plates have equal and opposite charge. When the space between them is evacuated, the electric field between the plates is 2 × 105 V/m. When the space is filled with dielectric, the electric field becomes 1 × 105 V/m. The dielectric constant of the dielectric material
  • 1/2
  • 1
  • 2
  • 3
The insulation property of air breaks down at E = 3 × 106 volt / metre. The maximum charge that can be given to a sphere of diameter 5 m is approximately (in coulombs)
  • 2 × 10–2
  • 2 × 10–3
  • 2 × 10–4
  • 2 × 10–5
Two spheres A and B of radius 4 cm and 6 cm are given charges of 80 µc and 40 µc respectively. If they are connected by a fine wire, the amount of charge flowing from one to the other is
  • 20µC from A to B
  • 16µC from A to B
  • 32µC from B to A
  • 32µC from A to B
In identical mercury droplets charged to the same potential V coalesce to form a single bigger drop. The potential of new drop will be

  • Physics-Electrostatics I-70818.png
  • 2)
    Physics-Electrostatics I-70819.png

  • Physics-Electrostatics I-70820.png

  • Physics-Electrostatics I-70821.png
An uncharged sphere of metal is placed in between two charged plates as shown. The lines of force look like
Physics-Electrostatics I-70823.png
  • A
  • B
  • C
  • D
The intensity of the electric field required to keep a water drop of radius 10–5 cm just suspended in air when charged with one electron is approximately (g = 10 newton / kg, e = 1.6 × 10–19 coulomb)
  • 260 volt/cm
  • 260 newton /coulomb
  • 130 volt/cm
  • 130 newton /coulomb
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