A charge Q is distributed over three concentric spherical shells of radii a , b , c a < b < c such that their surface charge densities are equal to one another. The total potential at a point at distance r from their common centre, where r < a , would be:

Q a + b + c 4 π ϵ 0 a 2 + b 2 + c 2

Q a 2 + b 2 + c 2 4 π ϵ 0 a 3 + b 3 + c 3

Q 12 π ϵ 0 a b + b c + c a a b c

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Charge is distributed within a sphere of radius $R$ with a volume charge density $ρ (r) = \frac{A}{r^{2}} e^{- \frac{2 r}{a}},$ where $A$ and $a$ are constants. If $Q$ is the total charge of this charge distribution, the radius $R$ is_____.

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Important Questions on Electrostatics

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Alpha Question Bank for Medical: Physics>Chapter 22 - Electrostatics>Exercise-3>Q 45

Two electric dipoles, $A,$ $B$ with respective dipole moments $\vec{d_{A}} = - 4 q a \hat{i}$ and $\vec{d_{B}} = - 2 q a \hat{i}$ are placed on the $x$ -axis with separation $R,$ as shown in the figure
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The distance from $A$ at which both of them produce the same potential is:

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Alpha Question Bank for Medical: Physics>Chapter 22 - Electrostatics>Exercise-3>Q 46

Four equal point charges

Q

each are placed in the

x y

plane at

(0, 2), (4, 2), (4, - 2)

and

(0, - 2)

. The work required to put a fifth charge

Q

at the origin of the coordinate system will be:

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Alpha Question Bank for Medical: Physics>Chapter 22 - Electrostatics>Exercise-3>Q 47

Charges $- q$ and $+ q$ located at $A$ and $B,$ respectively, constitute an electric dipole. Distance $A B =$ $2 a, O$ is the mid point of the dipole and $O P$ is perpendicular to $A B .$ A charge $Q$ is placed at $P$ where $O P = y$ and $y > > 2 a .$ The charge $Q$ experiences an electrostatic force $F .$ If $Q$ is now moved along the equatorial line to $P^{'}$ such that $O P^{'} = (\frac{y}{3}),$ the force on $Q$ will be close to: $(\frac{y}{3} > 2 a)$

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Alpha Question Bank for Medical: Physics>Chapter 22 - Electrostatics>Exercise-3>Q 48

The given graph shown variation (with distance $r$ from centre) of:

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Alpha Question Bank for Medical: Physics>Chapter 22 - Electrostatics>Exercise-3>Q 49

Three charges

Q, + q

and

+ q

are placed at the vertices of a right-angle isosceles triangle as shown below. The net electrostatic energy of the configuration is zero, if the value of

Q

is :

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Alpha Question Bank for Medical: Physics>Chapter 22 - Electrostatics>Exercise-3>Q 50

An electric field of

1000 V m^{- 1}

is applied to an electric dipole at angle of

45 °

. The value of electric dipole moment is

10^{- 29} C m

. What is the potential energy of the electric dipole?

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Alpha Question Bank for Medical: Physics>Chapter 22 - Electrostatics>Exercise-3>Q 52

There is a uniform spherically symmetric surface charge density at a distance

R_{0}

from the origin. The charge distribution is initially at rest and starts expanding because of mutual repulsion. The figure that represents best the speed

V (R (t))

of the distribution as a function of its instantaneous radius

R (t)

is:

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Alpha Question Bank for Medical: Physics>Chapter 22 - Electrostatics>Exercise-3>Q 53

Dependence of intensity of gravitational field $(E)$ of earth with distance $(r)$ from centre of earth is correctly represented by:

Charge is distributed within a sphere of radius R with a volume charge density ρr=Ar2e-2ra, where A and a are constants. If Q is the total charge of this charge distribution, the radius R is_____.

Important Questions on Electrostatics

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Charge is distributed within a sphere of radius $R$ with a volume charge density $ρ (r) = \frac{A}{r^{2}} e^{- \frac{2 r}{a}},$ where $A$ and $a$ are constants. If $Q$ is the total charge of this charge distribution, the radius $R$ is_____.