Electric Charges and Fields Quiz Set-3

Question 1

Which of the following statements is true regarding the quantization of electric charge?

Accepted Answer

Charge always exists as an integral multiple of the fundamental charge $e$.

Answer

Charge can exist in fractions of electron charge.

Answer

The total charge of an isolated system is not conserved.

Answer

Quantization of charge is only valid for microscopic charges.

Question 2

Two point charges $+3\mu C$ and $+4\mu C$ repel each other with a force of $10 N$. If each is given an additional charge of $-6\mu C$, the new force will be:

Accepted Answer

$2 N$ (attractive)

Answer

$2 N$ (repulsive)

Answer

$4 N$ (repulsive)

Answer

$4 N$ (attractive)

Question 3

The electric flux through a closed surface enclosing an electric dipole is:

Accepted Answer

Zero

Answer

$\frac{q}{\epsilon_0}$

Answer

$\frac{2q}{\epsilon_0}$

Answer

Infinite

Question 4

An electric dipole of dipole moment $\vec{p}$ is placed in a uniform electric field $\vec{E}$. The torque $\vec{	au}$ acting on it is given by:

Accepted Answer

$\vec{	au} = \vec{p} 	imes \vec{E}$

Answer

$\vec{	au} = \vec{p} \cdot \vec{E}$

Answer

$\vec{	au} = \vec{E} 	imes \vec{p}$

Answer

$\vec{	au} = pE$

Question 5

Which of the following graphs correctly represents the variation of electric field $E$ due to a uniformly charged infinite plane sheet with distance $r$ from it?

Accepted Answer

$E$ is independent of $r$

Answer

$E \propto r$

Answer

$E \propto 1/r$

Answer

$E \propto 1/r^2$

Question 6

A charge $q$ is placed at the center of a cube of side $L$. The electric flux emerging from the cube is:

Accepted Answer

$\frac{q}{\epsilon_0}$

Answer

$\frac{q}{6\epsilon_0}$

Answer

$\frac{6qL^2}{\epsilon_0}$

Answer

$\frac{q}{8\epsilon_0}$

Question 7

The SI unit of electric flux is:

Accepted Answer

$N m^2 C^{-1}$

Answer

$N C^{-1} m^{-2}$

Answer

$N C m^{-2}$

Answer

$N m^{-2} C$

Question 8

If the distance between two point charges is doubled, the electrostatic force between them becomes:

Accepted Answer

One-fourth

Answer

Four times

Answer

Two times

Answer

Halved

Question 9

An electron enters a uniform electric field with an initial velocity perpendicular to the field lines. The trajectory of the electron is:

Accepted Answer

Parabolic

Answer

Straight line

Answer

Circular

Answer

Elliptical

Question 10

Four charges are placed at the corners of a square ABCD. The charge at A is $+q$, at B is $+2q$, at C is $-q$, and at D is $-2q$. The direction of the electric field at the center of the square is along:

Accepted Answer

CB

Answer

AB

Answer

BD

Answer

AC

Question 11

What is the angle between the electric dipole moment and the electric field strength due to it on the equatorial line?

Accepted Answer

$180^\circ$

Answer

$0^\circ$

Answer

$90^\circ$

Answer

$45^\circ$

Question 12

A hollow metal sphere of radius $R$ is uniformly charged. The electric field at a distance $r$ ($r < R$) from the center is:

Accepted Answer

Zero

Answer

Non-zero constant

Answer

Proportional to $r$

Answer

Inversely proportional to $r^2$

Question 13

Two charges $q_1$ and $q_2$ are placed in vacuum at a distance $d$ and the force acting between them is $F$. If a medium of dielectric constant $K=4$ is introduced around them, the force will be:

Accepted Answer

$F/4$

Answer

$4F$

Answer

$2F$

Answer

$F/2$

Question 14

The electric field intensity due to a short dipole at a distance $r$ along the axial line is $E_a$ and along the equatorial line is $E_e$. The relation between them is:

Accepted Answer

$E_a = 2E_e$

Answer

$E_a = E_e$

Answer

$E_e = 2E_a$

Answer

$E_a = 4E_e$

Question 15

A point charge $+10 \mu C$ is at a distance 5 cm directly above the center of a square of side 10 cm. The magnitude of the electric flux through the square is:

Accepted Answer

$1.88 	imes 10^5 N m^2 C^{-1}$

Answer

$1.88 	imes 10^4 N m^2 C^{-1}$

Answer

$1.88 	imes 10^6 N m^2 C^{-1}$

Answer

Zero

Question 16

Which of the following properties is NOT true for electric field lines?

Accepted Answer

They form closed loops.

Answer

They start from positive charge and end on negative charge.

Answer

They never cross each other.

Answer

They are normal to the surface of a charged conductor.

Question 17

If $\oint \vec{E} \cdot d\vec{s} = 0$ over a surface, then:

Accepted Answer

The number of flux lines entering the surface must be equal to the number of flux lines leaving it.

Answer

The electric field inside the surface and on the surface is zero.

Answer

The electric field inside the surface is necessarily uniform.

Answer

All charges must necessarily be outside the surface.

Question 18

The dimensional formula for Permittivity of free space ($\epsilon_0$) is:

Accepted Answer

$[M^{-1} L^{-3} T^4 A^2]$

Answer

$[M L^3 T^{-4} A^{-2}]$

Answer

$[M^{-1} L^3 T^{-2} A]$

Answer

$[M L^{-3} T^3 A^2]$

Question 19

A polythene piece rubbed with wool is found to have a negative charge of $3 	imes 10^{-7} C$. The number of electrons transferred is:

Accepted Answer

$1.875 	imes 10^{12}$

Answer

$1.875 	imes 10^{11}$

Answer

$1.875 	imes 10^{10}$

Answer

$2 	imes 10^{12}$

Question 20

Three charges $+q$, $+q$, and $+q$ are placed at the vertices of an equilateral triangle of side $a$. The force on a charge $+Q$ placed at the centroid of the triangle is:

Accepted Answer

Zero

Answer

$\frac{3Qq}{4\pi\epsilon_0 a^2}$

Answer

$\frac{Qq}{2\pi\epsilon_0 a^2}$

Answer

$\frac{\sqrt{3}Qq}{4\pi\epsilon_0 a^2}$

Questions in this Quiz

Related Quizzes

More Quizzes for Class 12

Frequently Asked Questions

Electric Charges and Fields Quiz Set-3

Questions in this Quiz

Related Quizzes

More Quizzes for Class 12

Chemistry

Mathematics

Physics

Frequently Asked Questions

What specific topics does this Class 12 Physics quiz cover?

Are these questions suitable for CBSE Board exam preparation?

What is the difficulty level of this Physics quiz?

Can this quiz help with JEE or NEET preparation?

Does the quiz include numerical problems?