Question 1 :
The field at a distance $r$ from a long straight wire of charge per unit length $\lambda$ is:

Question 2 :
Calculate the excess number of electrons on each of two similar charged spheres that are located 5 cm apart (in air),such that the force of repulsion between them is 36 x 10$^{-19}$N

Question 3 :
A total charge of&#160;$\displaystyle 5\mu c$ is distributed uniformally on the surface of the thin walled semi spherical cup. If the electric field strength at the center of the semi sphere is&#160;$\displaystyle 9\times { 10 }^{ 8 }N{ C }^{ -1 }$, the radius of the cup is:<br/>$\displaystyle \left( \frac { 1 }{ 4\pi { \in &#160;}_{ 0 } } =9\times { 10 }^{ 9 }N{ m }^{ 2 }{ C }^{ -2 } \right)&#160;$<br/>

Question 5 :
<p>An electric dipole moment $\overrightarrow {\rm{P}} {\rm{ = }}\left( {{\rm{2}}{\rm{.0}}\widehat {\rm{i}}{\rm{ + 3}}{\rm{.0}}\widehat {\rm{j}}} \right){\rm{\mu C}}{\rm{.}}$.m is placed in a uniform electric<br>field$\overrightarrow E {\rm{ = }}\left( {{\rm{3}}{\rm{.0}}\widehat {\rm{i}}{\rm{ + 2}}{\rm{.0}}\widehat k} \right) \times {10^5}$</p>

Question 6 :
A charge Q is divided into two parts. The two charges kept at a distance apart have a maximum columbian repulsion. Then the ratio of Q and one of the parts is given by :

Question 7 :
An electric dipole is placed in non-uniform electric field, then it experiences

Question 9 :
What will be the magnitude of torque on an electric dipole having dipole moment of $4\times { 10 }^{ -9 }cm$ placed in a uniform electric field of intensity of $5\times { 10 }^{ 4 \,\,}N { C }^{ -1 }$ making an angle ${180}^{o}$ with the field.

Question 10 :
<span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small"><p class="wysiwyg-text-align-left">A particle that carries a charge $-q$ is placed at rest in uniform electric field $10\ N/C$. It experiences a force and moves in a certain time t, it is observed to acquire a velocity $10\vec{i}-10\vec{j}$ m/s. The given electric field intersects a surface of area $A$ $m^{2}$in the X -Z plane. Electric flux through surface is:</p>

Question 11 :
The ratio of the energy required to set up in cube of side 10 cm uniform magnetic field of 4${ Wb/m }^{ 2 }$ and a uniform electric field of $10^{ 6 }V/m$ is:

Question 12 :
The value of distance $r_m$, inside the ball at which electric field intensity maximum is given by-

Question 13 :
The radii of two conducting sphere are $ a $ and $ b $. They are charged by equal charge density. What would be the ratio of the electric field intensities at their surface?

Question 14 :
Two charged spheres having radii a and b are joined with a wire then the ratio of electric field $\dfrac{E_a}{E_b}$ on their surface is?

Question 15 :
Charges $Q_1$ and $Q_2$ lie inside and outside respectively of a closed surface S. Let E be the field at any point on S and $\phi$ be the flux of E over S.

Question 16 :
A particle of mass $m$ and charge $q$ at rest is released in a uniform electric field between parallel planes of charge $+q$ and $-q$ respectively. The particle accelerates towards the other place a distance $'d'$ away. The speed at which it strikes the opposite plane is:

Question 17 :
A particle of mass m and charge -q moves diametrically through a uniformly charged sphere of radius R with total charge Q. The angular frequency of the particle's simple harmonic motion, if its amplitude &lt; R, is given by :

Question 18 :
Two infinitely long parallel conducting plates having surface charge densities$\displaystyle +\sigma$ and$\displaystyle -\sigma$respectively, are separated by a small distance. The medium between the plates is vacuum. If$\displaystyle { \varepsilon }_{ 0 }$is the dielectric permittivity of vacuum then the electric field in the region between the plates is:

Question 19 :
Charges $Q_1$ &#160; and&#160; $Q_2$ lie inside and outside, respectively, of a closed surface S. Let E be the field at any point on S and $\phi$ be the flux of E over S.

Question 20 :
A solid sphere of radius $R$ has a charge $Q$ distributed in its volume with a charge density $\rho = kr^{a}$, where $k$ and $a$ are constants and $r$ is the distance from its centre. If the electric field at $r = \dfrac {R}{2}$ is $\dfrac {1}{8}$ times that at $r = R$, the value of $a$ is