# Physics Quiz: Practice Questions On Electromagnetic Fields!

41 Questions | Attempts: 500  Settings  Do you know what an electronic field is? An electronic field is a non-quantum field produced by accelerating electric charges. It is the field described by electrodynamics and is the counterpart to the quantized electromagnetic field. The electromagnetic field possesses magnetic and electrical properties and surrounds objects with an electrical charge. Whenever a voltage is present, an electric field forms, this quiz will tell you about electromagnetic fields. Don’t forget to procure your certificate when you are done.

• 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.

• B.

• 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.
Which of the following statement for a divergence of electric and magnetic flux densities?
• 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.
Which of this statement is not characteristic of a static magnetic field?
• 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

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