Physics Quiz: Practice Questions On Electromagnetic Fields!

41 Questions | Total Attempts: 300

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Physics Quiz: Practice Questions On Electromagnetic Fields!

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Questions and Answers
  • 1. 
    .The electric flux is given D = (2y2 + z) Ix + 4xy Iy + x 1z C/m2(Ix,Iy and Iare the unit vectors along x , y and z directions). The volume charge density at point (-1,0,3) is
    • A. 

      0 C/m3.

    • B. 

      - 2 C/m3.

    • C. 

      - 4 C/m3.

    • D. 

      - 8 C/m3

  • 2. 
    Gradient of scalar field is expressed as 
    • A. 

      Outward flux of a vector field per unit volume as the volume about the point tends to zero.

    • B. 

      Gradient of divergence of a vector field minus the curl of the vector field.

    • C. 

      Circulation of a vector field per unit area as the area tends to zero.

    • D. 

      Maximum rate of increase of scalar function at appoint.

  • 3. 
    Which of following is zero?
    • A. 

      Grad div A.

    • B. 

      Div Gradient V.

    • C. 

      Div curl A.

    • D. 

      Curl curl A.

  • 4. 
    Which statement does not say that electrostatic field conservative?
    • A. 

      If the curl of E is identically zero.

    • B. 

      The potential difference between two points is zero.

    • C. 

      If is gradient of a scalar potential.

    • D. 

      The work done in a closed path inside the fields is zero.

  • 5. 
    If E is the electric field intensity, then what is the value of divergence of (curl of E)?.
    • A. 

      E.

    • B. 

      | E |.

    • C. 

      Null vector.

    • D. 

      Zero.

  • 6. 
    Two sphere of radius r1 and r2 are connected by a conducting wire. Each of the spheres has been given a charge Q. Now
    • A. 

      Larger sphere will have greater potential.

    • B. 

      Larger sphere will have smalled potential.

    • C. 

      Both of sphere will have same potential

    • D. 

      Smaller sphere will have zero potential.

  • 7. 
    • A. 

      Both are zero.

    • B. 

      It is zero for the electric flux density.

    • C. 

      These are zero for static densities but non zero for time varying densities.

    • D. 

      It is zero for the magnetic flux density.

  • 8. 
    • A. 

      It is conservatives.

    • B. 

      It is solenoidal.

    • C. 

      It has no sink or sources.

    • D. 

      Magnetic flux lines are always closed.

  • 9. 
    For gauss's law the point charges in closed surface must be distributed
    • A. 

      arbitrarily

    • B. 

      sequentially

    • C. 

      rational

    • D. 

      in line

  • 10. 
    Gauss's law due to different charge distribution is used to calculate
    • A. 

      electric field

    • B. 

      electric charge

    • C. 

      electric intensity

    • D. 

      electric field lines

  • 11. 
    The field lines parallel to the sides of box will have flux that is
    • A. 

      1

    • B. 

      min

    • C. 

      0

    • D. 

      Max

  • 12. 
    The law stated as flux is 1/eo times the total charge is
    • A. 

      Ohms law

    • B. 

      Newton's law

    • C. 

      Gauss's law

    • D. 

      Coulombs law

  • 13. 
    The law stating the force directly proportional to charges and inversely proportional to the square of radius is called
    • A. 

      Newton's law

    • B. 

      Coulombs law

    • C. 

      Gauss's law

    • D. 

      4ohms law

  • 14. 
    Two positive charges q1 = 16 and q2 = 4 are separated by a diameter of 3m will produce the force of
    • A. 

      40N

    • B. 

      41.1N

    • C. 

      42.3N

    • D. 

      42.7N

  • 15. 
    The formula that describes the statement of the coulombs law is
    • A. 

      F = kq1q2/r2

    • B. 

      F = q1q2/r2

    • C. 

      F = kq2/r2

    • D. 

      F = kq1q2/r

  • 16. 
    Two metal spheres of radii R1 and R2 are charged to the same potential. The ratio of charges on the spheres 1 and 2 is 
    • A. 

      √R1 : √R2

    • B. 

      1:1

    • C. 

      R1 : R2

    • D. 

      R1³ : R2³

  • 17. 
    A simple pendulum has a metal bob, which is negatively charged. If it is allowed to oscillate above. a positively charged metallic piate, then its time period will 
    • A. 

      Increases

    • B. 

      Become zero

    • C. 

      Decreases

    • D. 

      Remain the same

  • 18. 
    A sphere of radius 1 em has potential of 8000 V, then energy density near its surface will be
    • A. 

      64 x 10⁵ J/m³

    • B. 

      8 x 10³ J/m³

    • C. 

      32 J/m³

    • D. 

      2.83 J/m³

  • 19. 
    Two plates are 2 cm apart, a potential is applied between them, the electric field difference of 10 volts is applied between them, the electric field between the plates is
    • A. 

      20 N/C

    • B. 

      5 N/C

    • C. 

      500 N/C

    • D. 

      250 N/C

  • 20. 
    The radius of a soap bubble whose potential is 16 Vis doubled. The new potential of the bubble will be 
    • A. 

      2 V

    • B. 

      8 V

    • C. 

      4 V

    • D. 

      16 V

  • 21. 
    A hollow metal sphere of radius 5 cm is charged such that the potential on its surface is 10 V. The potential at a distance of 2 cm from the centre of the sphere
    • A. 

      Zero

    • B. 

      4 V

    • C. 

      10 V

    • D. 

      10/3 V

  • 22. 
    A radioactive source in the form of a metal sphere of radius 10-2 m, emits beta particles at the rate of 5 x 1010 partiCles per sec. The source is electrically insulated. How long will it take for it's potential to be raised by 2 volts, assuming 40% of the emitted beta particles escape the source
    • A. 

      700 sec

    • B. 

      700 μ sec

    • C. 

      700 milli sec

    • D. 

      700 n sec

  • 23. 
    A conducting sphere of radius R, and carrying a charge q is joined to a conducting sphere of radius 2R, and carrying a charge - 2q. The charge flowing between them will be
    • A. 

      Q/3

    • B. 

      Q

    • C. 

      2q/3

    • D. 

      4q/3

  • 24. 
    The solution of Laplace equation has no. of solutions for a given charge configuration
    • A. 

      One

    • B. 

      Two

    • C. 

      More than two

    • D. 

      Infinite

  • 25. 
    A sphere of radius r is placed concentrically inside a hollow sphere of radius R. The bigger and smaller spheres are given charges Q and q respectively and are insulated. The potential difference between the two .spheres depends on
    • A. 

      Only charge q

    • B. 

      Both q and Q

    • C. 

      Only charge Q

    • D. 

      None on q and Q