# Physics Quiz: Practice Questions On Electromagnetic Fields!

41 Questions | Total Attempts: 300  Settings  .

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• 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.
• 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