Electric fields and charges practice · Mixed difficulty

Electrical force between two point charges is 200N. If we increase 10% charge on one of the charges and decrease 10% charge on the other, then electrical force between them for the same distance becomes __________ N

Two insulated charged metallic spheres $P$ and $Q$ have their centres separated by a distance of $50 \mathrm{~cm}$. The radii of $P$ and $Q$ are negligible compared to the distance of separation. The mutual force of electrostatic repulsion if the charge on each is $3.2 \times 10^{-7} \mathrm{C}$ is:

A comb run through one’s dry hair attracts small bits of paper. This is due to

Two equal negative charges $-q$ are fixed at the points $(0, a)$ and $(0,-a)$ on the $y$-axis. A positive charge $Q$ is released from rest from the point $(2 a, 0 )$ on the $x$-axis. The charge will

$F_g$ and $F_e$ represents gravitational and electrostatic force respectively between electron and proton at a distance of $10 \mathrm{~cm}$. The ratio of $F_g / F_e$ is of the order of

A positively charged thin metal ring of radius
$R$ is fixed in the xy-plane, with its centre at the
origin. A negatively charged particle is released
from rest at the point $P (0, 0, c)$ where $c > 0.$

Consider the following statements:
(A) The electric field at $P$ due to the metallic ring
is always directed towards origin.

(B) The negatively charged particle is accelerated
towards origin and undergoes periodic
motion.

Which of the above statements is/are correct?

Additive nature of charge means

A capacitor of capacitance $C$ is charged to potential $V.$ The flux of the electric field through a closed surface enclosing the capacitor is

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

A tin nucleus (atomic number Z = 50) has a radius of $6.6 \times {10^{ - 15}}\,m$. The potential on its surface will be (the charge on the proton $= 1.6 \times {10^{ - 19}}\,C$)

A thin metallic spherical shell contains a charge $Q$ on its surface. A point charge $\mathrm{q}_1$ is placed at the centre of the shell and another charge $\mathrm{q}_2$ is placed outside the shell. All the three charges are positive. Then the force on charge $\mathrm{q}_1$ is -

Let there be a spherically symmetric charge distribution with charge density varying as $\rho(r)=\rho_0\left[\frac{2}{3}-\frac{2 r}{R}\right]$ upto $r=R$ and $\rho(r)=0$ for $r>R$, where $r$ is the distance from origin. The electric field at a distance $r(r < R)$ from the origin is given by:

When a body is earth connected, electrons from the earth flow into the body. This means the body is

Statement-1: Electric field outside the uniformly charged spherical shell (due to shell) is the same as that of a point charge at its center.
Statement-2: The centre of mass of uniform shell is at its center.

A mass of $1 \mathrm{~kg}$ carrying a charge of $2 \mathrm{~C}$ is accelerated through a potential of $1 \mathrm{~V}.$ The velocity acquired by it is:

Five balls numbered 1 to 5 are suspended using separate threads. Pairs $(1,2),(2,4)$ and $(4,1)$ show electrostatic attraction, while pair $(2,3)$ and $(4,5)$ show repulsion. Therefore ball 1 must be

Under the action of a given coulombic force the acceleration of an electron is $2.5 \times {10^{22}}\mathrm{m}/{\mathrm{s}^2}.$ Then the magnitude of acceleration of a proton under the action of same force is nearly

The magnitude of electric field intensity at a point outside uniformly charged thin infinite plane sheet is independent of

A point charge $q$ produces an electric field of magnitude $2$ $\mathrm{N}{\mathrm{C}^{ - 1}}$ at a point distance $0.25\;\mathrm{ }m$ from it. What is the value of charge?

Statement-1: When a charge is placed at rest in an electric field its path will always be along electric line of force.
Statement-2: The force on the charge is along the tangent drawn on electric field line.

A certain charge $Q$ is divided into two parts let’s say $q_1$ and $q_2$ then these two point charges are placed at a certain distance apart. The ratio $\frac{{{q_1}}}{{{q_2}}},$ for which the electrostatic force between them will be maximum

Four metal conductors having different shapes 1. A sphere 2. Cylindrical 3. Pear 4. Lightning conductor Are mounted on insulating stands and charged. The one which is best suited to retain the charges for a longer time is

The electrostatic force between two point charges is directly proportional to the

A sphere of radius 1 m encloses a charge of $5\mu C.$ Another charge of $-5 \mu C$ is placed inside the sphere.
The net electric flux would be

The number of electric lines that emerge from a finite charge $+q$ is

Assertion:- Electric field inside a metal surface is zero in electrostatic condition.
Reason:-Electric charges exist only on the surface of conductor.

Which is not the unit of electric field :

The force of interaction between two charges ${q_1} = 6\mu \;$ C and ${q_2} = 2\mu$ C is 12 N. If charge $q = - 2\mu$ C is added to each of the charges, then the new force of interaction is

One moving electron when comes closer to
other stationary electron, then its kinetic
energy and potential energy respectively _____
and _____

A point charge $+ q$ is placed at the midpoint of a cube of side $a$. The electric flux emerging from the cube is