MCQ Questions for Class 12 Medical Physics Electric Charges And Fields Quiz 15

Two infinite linear charge are placed parallel at 0.1 m apart. It has density of 5

$\mu$ C/m,then the force per unit length of one of linear charges in N/m is;

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2.5
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3.25
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4.5
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7.5

The electric field in a region is given by

$\vec{E}=a\hat{i}+b\hat{j}$ . Here a and b are constants. Find the net flux passing through a square area of side

$l$ parallel to y-z plane:

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$al^{2}$
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$bl^{2}$
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Zero
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$(a+b)l^{2}$

A charge Q is placed at the centre of cube. The electric flux emerging from any one surface of the cube is .

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$\dfrac { Q }{ { \varepsilon }_{ 0 } }$
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$\dfrac { Q }{ 2{ \varepsilon }_{ 0 } }$
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$\dfrac { Q }{ 4{ \varepsilon }_{ 0 } }$
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$\dfrac { Q }{ 6{ \varepsilon }_{ 0 } }$

Identify the wrong statement in the following. Coulomb's law correctly describes the electric force that

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Binds the electrons of an atom to its nucleus
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Binds the protons and neutrons in the nucleus of an atom
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Binds atoms together to form molecules
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Binds atoms and molecules together to form solids

A charge

$Q\mu C$ is placed at the center of a cube, the flux coming out from three face will be (in coulomb) :

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$\dfrac { Q }{ 6{ \varepsilon }_{ 0 } } \times { 10 }^{ -6 }$
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$\dfrac { Q }{ 2{ \varepsilon }_{ 0 } } \times { 10 }^{ -6 }$
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$\dfrac { 3Q }{ { \varepsilon }_{ 0 } } \times { 10 }^{ -6 }$
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$\dfrac { Q }{ 24{ \varepsilon }_{ 0 } } \times { 10 }^{ -6 }$

A point charge

$q$ is placed at a point inside a hollow conducting sphere. Which of the following electric force pattern is correct?

A hemispherical surface (half of a spherical surface) of radius

$R$ is located in a uniform electric field

$E$ that is parallel to the hemisphere. What is the magnitude of the electric flux through the hemisphere surface ?

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$0$
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$4 \pi R ^ { 2 } E / 3$
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$2 \pi R ^ { 2 } E$
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$\pi R ^ { 2 } E$

A dipole of dipole moment $\overline P = 2\widehat i - 3\widehat j + 4\widehat k$ is placed at point $A\left( {2, - 3,1} \right)$ . The electric potential due to this dipole at the point $B\left( {4, - 1,0} \right)$ is equal to ( All the parameters specified here are in S.I. units.)

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$2 \times {10^9}\;{\text{Volts}}$
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$- 2 \times {10^9}\;{\text{Volts}}$
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$3 \times {10^9}\;{\text{Volts}}$
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$- 3 \times {10^9}\;{\text{Volts}}$

In the given figure flux through surface

$S _ { 1 }$ is

$\phi _ { 1 }$

$\&$ through

$S _ { 2 }$ is

$\phi _ { 2 }.$ Which is correct ?

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$\phi _ { 1 } = \phi _ { 2 }$
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$\phi _ { 1 } > \phi _ { 2 }$
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$\phi _ { 1 } < \phi _ { 2 }$
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None of these

$+ q$ charge is placed inside any spherical surface then total flux coming out from whole surface will be -

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$q\times\epsilon_0$
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$\dfrac{q}{\epsilon_0}$
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$\dfrac{\epsilon_0}{q}$
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$\dfrac{q^2}{\epsilon_0}$

A charge q is placed at one corner of a cube. The electrons flux through any of the three faces adjacent to the charge is zero. The flux through any one of the other three is

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$q/3{ \epsilon }_{ 0 }$
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$q/6{ \epsilon}_{ 0 }$
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$q/12{ \epsilon }_{ 0 }$
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$q/24{ \epsilon}_{ 0 }$

The surface density of charge on a very large flat metal plate is

$2.25 \times 10^{-9} coul/m^2$ . The intensity of electric field at a point at a distance 20 cm from the middle part of plate is

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$90 \pi N/C$
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$100 \pi N/C$
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$45 \pi N/C$
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$81 \pi N/C$

A long cylindrical conductor, of radius

$5\mathrm { mm }$ and placed in a medium of permittivity

$55.55\mathrm { pF } / \mathrm { m } ,$ has surface charge density of

$2\mu \mathrm { C } / \mathrm { m } ^ { 2 } .$ The magnitude of the electric intensity at a point

$2\mathrm { m }$ from its axis is nearly

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$9 \mathrm { N } / \mathrm { C }$
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$90 \mathrm { N } / \mathrm { C }$
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$1.111 \times 10 ^ { 2 } \mathrm { N } / \mathrm { C }$
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$1.111 \times 10 ^ { -2 } \mathrm { N } / \mathrm { C }$

The electric flux

$\phi$ through a hemisphere surface of radius R, placed in a uniform electric field of intensity E parallel to the axis of its circular plane is:

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$2 \pi RE$
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$2 \pi R^2 E$
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$\pi R^2 E$
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$\pi R^3 E$

When a

$10\mu C$ charge is enclosed by a closed surface, the flux passing through the surface is

$\phi .$ Now another

$- 5\mu C$ charge is placed inside the same closed surface, then the flux passing through the surface is__________

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$2\phi$
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$\phi /2$
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$\phi$
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Zero

Given a uniform electric field

$E=5\times 10^3\hat{i} \ N/C$ , find the flux of this field through a square of

$10\ cm$ on a side whose plane is parallel to the

$y-z$ plane. What would be the flux through the square if the plane makes

$30^\circ$ angle with the x-axis.

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$23.3N/Cm^2$
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$25N/Cm^2$
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$33.3N/Cm^2$
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$43.3N/Cm^2$

A positive charge

$q$ is enclosed by a Gaussian spherical surface of radius '

$a$ ' . If its radius is increased to

$4a$ then the net outwards flux will

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Become four time
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Become two times
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Become sixten times
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Remain same

A point charge A of charge

$+4 \mu C$ and another point charge B of charge

$-1 \mu C$ are placed in air at a distance 1 meter apart . then the distance of the point on the line joining the charges and from the charge B , where the resultant electric field is zero , is ( in meter)

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$1.5$
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$0.5$
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$1$
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$2$

A wire of linear charge density

$\lambda$ passes through a cuboid of length

$l ,$ breadth

$b$ and height

$h$ in such a manner that flux through the cuboid is maximum. The position of wire is now changed, so that the flux through the cuboid is minimum.

$l > b > h ,$ then the ratio of maximum flux to minimum flux will be

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$\dfrac { \sqrt { 1 ^ { 2 } + b ^ { 2 } + h ^ { 2 } } } { h }$
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$\dfrac { \sqrt { l ^ { 2 } + b ^ { 2 } } } { h }$
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$\dfrac { h } { \sqrt { l ^ { 2 } + b ^ { 2 } } }$
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$\dfrac { l } { \sqrt { l ^ { 2 } + b ^ { 2 } + h ^ { 2 } } }$

Two charges

$+3.2 \times 10^{-19} and -3.2 \times 10^{-19} C$ placed

$2.4 \mathring { A }$ apart form an electric dipole.It is placed in a uniform electric field of intensity

$4 \times 10^5 V/m$ . The electric dipole moment is

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$15.36 \times 10^{-29} Cm$
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$15.36 \times 10^{-19} Cm$
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$7.68 \times 10^{-29} Cm$
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$7.68 \times 10^{-19} Cm$

Two identical metal spheres possess

$+ 60 C$ and

$- 20 C$ of charges. They are brought in contact and then separated by

$10 cm$ . The force between them

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$36\times10^{13}N$
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$36\times10^{14}N$
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$36\times 10^{12}N$
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$3.6\times 10^{12}N$

A current

$I$ flows through a cylindrical rod of uniform cross-section area

$A$ and resistivity

$\rho$ . The electric flux through the shaded cross-section of rod as shown in figure is :

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$2 pI$
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$pI$
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$\dfrac { pI }{ A }$
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$\dfrac { pA }{ I }$

The electric flux through the surface

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in Fig. (iv) is the largest
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in Fig. (iii) is the least
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in Fig. (ii) is same as Fig. (iii) but is smaller then Fig (iv)
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is the same for all the figures

In a region the electric potential is given by

$V = 2x + 2y - 3z$ obtain the expression for electric field.

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$-2\hat {i} - 2\hat {j} + 3\hat {k}$
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$3\hat {i} + 4\hat {j} - 2\hat {k}$
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$2\hat {i} - 2\hat {j} - 3\hat {k}$
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None of these

The force of intraction of two dipoles, if the two dipole moments are parallel to each other and placed at a distance

$x$ apart.

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$\dfrac {3p_{1}p_{2}}{4\pi \epsilon_{0}x^{4}}$
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$\dfrac {p_{1}p_{2}}{4\pi \epsilon_{0}x^{4}}$
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$\dfrac {p_{1}p_{2}}{4\pi \epsilon_{0}x^{4}}$
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$\dfrac {p_{1}p_{2}}{3\pi \epsilon_{0}x^{4}}$

Mark correct option:
Electrostatic experiment is

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Affected on the humid day
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Not affected on humid day
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Independent of medium
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None of the above

A long thread carrying a uniform charge

$\lambda$ per unit length has the configuration shown in the figure. An element of charge

$q$ is cut from the thread. The cutting portion is shown as small gap

$(AB)$ . The electric field at the point

$O$ is

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Zero
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$\dfrac {q}{4\pi \varepsilon_{0}R^{2}}$
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$\dfrac {q}{2\pi \varepsilon_{0}R^{2}}$
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None of these

The electric lines of force are represented by the equation

$x^2+y^2=1$ . A unit positive charge initially at rest at point

$(1,0)$ will move.

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along the circular line of force
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at right angles to circular line of force
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along equidistant parallel lines of force
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at right angles to equidistant parallel lines of force

A charged particle

$q$ is placed at the centre

$O$ of a cube of length

$L(A\ B\ C\ D\ E\ F\ G\ H)$ . Another same charge

$q$ is placed at a distance

$L$ from

$O$ . Then the electric flux through

$ABCD$ .

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$q/6\pi \epsilon_{0}L$
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Zero
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$q/2\pi \epsilon_{0}L$
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$q/3\pi \epsilon_{0}L$

In a region, an electric field

$\vec {E} = E_{0}\hat {i}$ is present. The potential of points

$A(a, 0, 0), B(0, b, 0), C(0, 0, c)$ and

$D(-a, 0, 0)$ and

$V_{A}, V_{B}, V_{C}$ and

$V_{D}$ respectively, then

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$V_{A} = V_{B} = V_{C} = V_{D}$
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$V_{B} = V_{C}$
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$V_{D} < V_{B} < V_{A}$
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None of these

Electric field in a plane varies like

$(2x\hat {i} + 2y\hat {j})N/C$ . If potential at infinity is taken as zero, potential at

$x = 2m, y = 2m$ is

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$8\ V$
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$-8\ V$
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Zero
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Infinity

Six negative equal charges are placed at the vertices of a regular hexagon.

$6q$ charge is placed at the centre of the hexagon. The electric dipole moment of the system is

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Zero
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$6qa$
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$3qa$
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None of the above

Electric dipole moment of combination shown in the figure, is

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$qa + qa\sqrt {2} + qa$
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$2\sqrt {2}qa$
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$\sqrt {2}qa$
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$(\sqrt {2} + 1)qa$

Each of the following figures shows electric field vectors at two points A and Bin an electric field. In which figure or figures can the illustrated field be created by a single point charge?

Electric charges

$q , q , - 2q$ are placed at the corners of an equilateral triangle ABC of sides l . The magnitude of electric dipole moment of the system is

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$ql$
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$2 ql$
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$\sqrt{3} ql$
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$4 ql$

CBSE Questions for Class 12 Medical Physics Electric Charges And Fields Quiz 15 - MCQExams.com

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Practice Class 12 Medical Physics Quiz Questions and Answers

CBSE Questions for Class 12 Medical Physics Electric Charges And Fields Quiz 15 - MCQExams.com

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Practice Class 12 Medical Physics Quiz Questions and Answers

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