A uniformly charged solid sphere of radius R has potential V 0 (measured with respect to ∞ ) on its surface. For this sphere the equipotential surfaces with potential 3 V 0 2 , 5 V 0 4 , 3 V 0 4 and V 0 4 have radius R 1 , R 2 , R 3 and R 4 respectively. Then Note : This question had two option correct at the time of examination. Proper corrections are made in the question to avoid it.

R 1 ≠ 0 and R 2 - R 1 > ( R 4 - R 3 )

Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R. Assertion A : Two metallic spheres are charged to the same potential. One of them is hollow and another is solid, and both have the same radii. Solid sphere will have lower charge than the hollow one. Reason R : Capacitance of metallic spheres depend on the radii of spheres. In the light of the above statements, choose the correct answer from the options given below.

Both A and R are true and R is the correct explanation of A

Both A and R are true but R is not the correct explanation of A

Let σ be the uniform surface charge density of two infinite thin plane sheets shown in figure. Then the electric fields in three different region E I , E I I and E I I I

E → I = - σ ∈ 0 n ^ , E → I I = 0 , E → I I I = σ ∈ 0 n ^

E → I = 2 σ ∈ 0 n ^ , E → I I = 0 , E → I I I = 2 σ ∈ 0 n ^

E → I = 0 , E → I I = σ ∈ 0 n ^ , E → I I I = 0

E → I = σ 2 ∈ 0 n ^ , E → I I = 0 , E → I I I = σ 2 ∈ 0 n ^

Considering a group of positive charges, which of the following statements is correct?

Net potential of the system cannot be zero at a point but net electric field can be zero at that point

Net potential of the system at a point can be zero but net electric field can't be zero at that point

Both the net potential and the net field can be zero at a point

Both the net potential and the net electric field cannot be zero at a point

HARD

JEE Main

IMPORTANT

Earn 100

A thin disc of radius $b = 2 a$ has a concentric hole of radius $a$ in it (see figure). It carries uniform surface charge $σ$ on it. If the electric field on its axis at a height $h (h < < a)$ from its centre is given as $C h$ then the value of $C$ is

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Important Questions on Electrostatics

MEDIUM

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 13 - Electrostatics>JEE Main - 10th April 2015>Q 149

In the given circuits

(a)

and

(b)

, switches

S_{1}

and

S_{2}

are closed at

t = 0

and kept close for a long time. The variation of currents in the two circuits for

t \geq 0

are shown in the options. (Figures are schematic and not drawn to scale.)
Question Image

MEDIUM

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 13 - Electrostatics>JEE Main - 10th April 2015>Q 150

If the capacitance of a nanocapacitor is measured in terms of a unit

u

, made by combining the electronic charge

e

, Bohr radius

a_{0}^{},

Planck's constant

h

and speed of light

c

then

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 13 - Electrostatics>JEE Main - 4th April 2015>Q 151

In the given circuit, charge

Q_{2}

on the

2 μ F

capacitor changes as C is varied from

1 μF

3 μ F

Q_{2}

as a function of 'C' is given properly by: (figures are drawn schematically and are not to scale)
Question Image

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 13 - Electrostatics>JEE Main - 4th April 2015>Q 152

A uniformly charged solid sphere of radius R has potential $V_{0}$ (measured with respect to $\infty$ ) on its surface. For this sphere the equipotential surfaces with potential $\frac{3 V_{0}}{2}, \frac{5 V_{0}}{4}, \frac{3 V_{0}}{4}$ and $\frac{V_{0}}{4}$ have radius $R_{1}$ , $R_{2}, R_{3}$ and $R_{4}$ respectively. Then

Note : This question had two option correct at the time of examination. Proper corrections are made in the question to avoid it.

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 13 - Electrostatics>JEE Main - 4th April 2015>Q 153

A long cylindrical shell carries positive surface charge

σ

in the upper half and negative surface charge

- σ

in the lower half. The electric field lines around the cylinder will look like figure given in:

(figures are schematic and not drawn to scale)

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 13 - Electrostatics>JEE Main - 11th April 2015>Q 154

In the figure is shown a system of four capacitors connected across a $10 V$ battery. The charge that will flow from switch S when it is closed is:
Question Image

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 13 - Electrostatics>JEE Main - 11th April 2015>Q 155

A wire of length

L = 20 c m

is bent into a semi-circular arc and the two equal halves of the arc are uniformly charged with charges

+ Q

and

- Q

as shown in the figure. The magnitude of the charge on each half is

|Q| = 10^{3} ε_{0}

, where

ε_{0}

is the permittivity of free the space. The net electric field at the centre

O

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 13 - Electrostatics>JEE Main - 11th April 2015>Q 156

An electric field

\vec{E} = (25 \hat{i} + 30 \hat{j}) N C^{- 1}

exists in a region of space. If the potential at the origin is taken to be zero then the potential at

x = 2 m

y = 2 m

is:

A thin disc of radius b=2a has a concentric hole of radius a in it (see figure). It carries uniform surface charge σ on it. If the electric field on its axis at a height hh<<a from its centre is given as Ch then the value of C is

Important Questions on Electrostatics

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A thin disc of radius $b = 2 a$ has a concentric hole of radius $a$ in it (see figure). It carries uniform surface charge $σ$ on it. If the electric field on its axis at a height $h (h < < a)$ from its centre is given as $C h$ then the value of $C$ is