Physics - Electric Charges Fields - Quiz-6

24 electric dipoles each of dipole moment 2 $μ$ Cm are packed inside a hollow sphere. The net electric flux through the sphere is

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$28 {μCm}^{2}$
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$28 \frac{{μNm}^{2}}{C}$
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Zero
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Infinity

Which of the following is not the property of charge?

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Like point charges repel each other
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For an isolated system, the net charge is conserved
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Specific charge is invariant
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Charge is quantized

Three charges q, and q and -2q are kept at three corners of an equilateral triangle of side a. The magnitude of the electric dipole moment of the arrangement is

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2qa
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qa $\sqrt{2}$
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qa $\sqrt{3}$
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qa

Charge Q is distributed uniformly in a spherical region of radius R. Which if the following roughly represents the variation of the electric field (E) versus distance (r) from the center of the sphere?

Two charges are arranged as shown in the figure. If the electric field at the center of the circle is along the negative y-axis, then $\frac{q_{1}}{q_{2}}$ is

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$\sqrt{3}$
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$\frac{1}{\sqrt{3}}$
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$\frac{1}{3}$
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$\frac{\sqrt{3}}{2}$

The electric field intensity which would be just sufficient to balance the weight of a particle of charge -10 $μC$ and mass 10 mg, is

(Take g = 10 $m / s^{2}$ )

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10 N/C, in an upward direction
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$10^{3}$ N/C, in a downward direction
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10 N/C, in a downward direction
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$10^{4}$ N/C, in an upward direction

Two charges are placed at a certain distance apart in the air. If a glass slab is introduced between them, then the force between the two charges will

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Become zero
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Decrease
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Increase
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Remain the same

A particle of mass m and charge q is placed at rest in a uniform electric field E and then released. The kinetic energy attained by the particle after moving a distance y is

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$q E y$
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$q E y^{2}$
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$q E^{2} y$
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$q^{2} E y$

Force of interaction between two bodies of the same nature of the charge

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Must be repulsive
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May be attractive
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Must be attractive
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Zero

At the three corners of an equilateral triangle, charges are placed as shown in the figure. The magnitude of the electric field at point O is

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$\frac{1}{4 π ε_{0}} \frac{2 Q}{r^{2}}$
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$\frac{1}{4 π ε_{0}} \frac{Q}{r^{2}}$
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$\frac{1}{4 π ε_{0}} \frac{Q \sqrt{2}}{r^{2}}$
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$\frac{1}{4 π ε_{0}} \frac{Q \sqrt{3}}{r^{2}}$

Two symmetrical parallel metal each of one side plate area A having charges $Q_{1} and - Q_{2}$ are placed at small separation. What will be the electric field at a point in between the plates?

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$\frac{Q_{1} + Q_{2}}{2 A ε_{0}}$
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$\frac{Q_{1} + Q_{2}}{4 A ε_{0}}$
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$\frac{Q_{1} - Q_{2}}{2 A ε_{0}}$
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$\frac{Q_{1} - Q_{2}}{4 A ε_{0}}$

An electric dipole of the moment $\vec{P}$ is released in a uniform electric field $\vec{E}$ from the position of maximum torque. The angular speed of the dipole when $\vec{P}$ becomes parallel to $\vec{E}$ will be [l = moment of inertia of dipole]

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$\sqrt{\frac{2 P E}{I}}$
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$\sqrt{\frac{P E}{I}}$
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$\sqrt{\frac{4 P E}{I}}$
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$\sqrt{\frac{2 I}{P E}}$

A charge Q is given to a conducting sphere of radius R. Now if a charge -Q is placed, as shown, at a distance r from the center, then the magnitude of the force of attraction between charges is

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$\frac{1}{4 {πε}_{0}} \frac{Q^{2}}{r^{2}}$
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< $\frac{1}{4 {πε}_{0}} \frac{Q^{2}}{r^{2}}$
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> $\frac{1}{4 {πε}_{0}} \frac{Q^{2}}{r^{2}}$
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$\frac{1}{4 {πε}_{0}} \frac{Q^{2}}{{(r - R)}^{2}}$

If the electric flux entering and leaving a closed surface are respectively of magnitude $ϕ_{1} and ϕ_{2}$ , then the electric charge inside the surface will be

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$ε_{0} (ϕ_{2} - ϕ_{1})$
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$(ϕ_{1} - ϕ_{2}) {/2ε}_{0}$
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$ε_{0} (ϕ_{2} + ϕ_{1})$
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$\frac{ϕ_{2} - ϕ_{1}}{ε_{0}}$

Electric field at an axial point of short dipole is $\vec{E_{1}}$ . If the electric field at the equatorial point of same dipole is $\vec{E_{2}}$ , then which of the following is correct?

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$\vec{E_{1}}$ . $\vec{E_{2}}$ < 0
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$\vec{E_{1}}$ . $\vec{E_{2}}$ > 0
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$\vec{E_{1}}$ . $\vec{E_{2}}$ = 0
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$\vec{E_{1}}$ . $\vec{E_{2}}$ = $\vec{0}$

A long thin rod is charged such that charge per unit length of the rod is $λ$ . The rod is inserted into a hollow spherical surface of radius R. Maximum electric flux coming out the surface is

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$\frac{λ R}{ε_{0}}$
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$\frac{2 λ π R^{2}}{ε_{0}}$
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$\frac{2 λ R}{ε_{0}}$
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$\frac{2 λ R^{2}}{ε_{0}}$

Two charges q and 4q are separated by a distance r. The neutral point(in between the line joining the charges) is at a distance:

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$\frac{r}{3} from q$
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$\frac{2 r}{3} from q$
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$2 r from q$
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$r from 4 q$

A positron and a proton are projected normally into a uniform electric field with equal kinetic energy. The trajectory followed by them are

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Circular with equal radius
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Elliptical with the same major and minor axis
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Parabolic with the identical trajectory
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Hyperbolic with the identical trajectory

The distance between two point charges is increased by 10%. The force of interaction

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Increases by 10%
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Decreases by 10%
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Decreases by 17%
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Increases by 17%

Cm is the SI unit of

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Electric flux
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Electric potential
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Electric dipole moment
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Electric field intensity

A solid sphere of radius R has a uniform distribution of electric charge in its volume. At a distance x from its center (x<R), the electric field is directly proportional to

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$\frac{1}{x^{2}}$
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$\frac{1}{x}$
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x
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$x^{2}$

An insulated sphere of radius R has a uniform charge density $ρ$ . The electric field at a distance r from the center of the sphere (r<R) is-

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$\frac{ρ r}{3 ε_{0}}$
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$\frac{ρ R}{3 ε_{0}}$
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$\frac{ρ r}{ε_{0}}$
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$\frac{ρ}{ε_{0}} R$

The electric flux from a cube of edge l is $ϕ$ . What will be its value if the edge of the cube is made 2l and the charge enclosed is halved?

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2 $ϕ$
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$\frac{1}{2} ϕ$
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4 $ϕ$
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$ϕ$

Three identical plates are kept as shown. Plate 1 is given -5Q charge and plate 3 is given Q charge. Electric field intensity at point x is

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$\frac{3 Q}{A ε_{0}} d o w n$
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$\frac{3 Q}{2 A ε_{0}} d o w n$
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$\frac{3 Q}{2 A ε_{0}} u p w a r d$
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$\frac{3 Q}{A ε_{0}} u p w a r d$

The equation of trajectory of a charged particle moving in xy plane in a uniform electric field maybe

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y = 2x + 8
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x = $y^{2}$ + 4
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y = 2 $x^{2}$ + 6
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All of these

A short electric dipole having dipole moment $p \hat{i}$ is placed at origin and a point charge +q is placed at point (0, r). The force on dipole due to charge is in:

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+x-direction
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-x-direction
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+y-direction
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-y-direction

A point charge q is placed at the center of the open face of a hemispherical surface as shown in the figure. The flux linked with the surface is:

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zero
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$\frac{q}{2 ε_{0}}$
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$\frac{q}{ε_{0}}$
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$q π r^{2}$

Order of q/m ratio of the proton, $α$ -particle and electron is

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e > p > $α$
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p > $α$ > e
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e > $α$ > p
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p > e > $α$

A body can be negatively charged by

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Giving excess of electrons to it
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Removing some electrons from it
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Giving some protons to it
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Removing some neutrons from it

An electric field in space is given by $(10 \hat{i} + 3 \hat{j} + 4 \hat{k})$ unit, then electric flux through a surface of area 1 unit lying in yz plane is

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10 units
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17 units
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30 units
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40 units

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Practice Physics Quiz Questions and Answers

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Practice Physics Quiz Questions and Answers

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