Electrostatics · Physics · KCET

A body has a charge of $-3.2 \mu \mathrm{C}$. The number of excess electrons will be

A point charge $A$ of $+10 \mu \mathrm{C}$ and another point charge $B$ of $+20 \mu \mathrm{C}$ are kept 1 m apart in free space. The electrostatic force on $A$ due to $B$ is $F_1$ and the electrostatic force on $B$ due to $A$ is $\mathbf{F}_2$. Then

A uniform electric field $E=3 \times 10^5 \mathrm{NC}^{-1}$ is acting along the positive $Y$-axis. The electric flux through a rectangle of area $10 \mathrm{~cm} \times 30 \mathrm{~cm}$ whose plane is parallel to the ZX -plane is

The total electric flux through a closed spherical surface of radius $r$ enclosing an electric dipole of dipole moment $2 a q$ is (Give $\varepsilon_0=$ permittivity of free space)

Under electrostatic conditien of a charged conductor, which among the following statements is true?

A cube of side 1 cm contains 100 molecules each having an induced dipole moment of $0.2 \times 10^{-6} \mathrm{C}-\mathrm{m}$ in an external electric field of $4 \mathrm{NC}^{-1}$. The electric susceptibility of the materials is ................ $\mathrm{~C^2N}^{-1} \mathrm{~m}^{-2}$

A positively charged glass rod is brought near uncharged metal sphere, which is mounted on an insulated stand. If the glass rod is removed, the net charge on the metal sphere is

In the situation shown in the diagram, magnitude, if $$q < < |Q|$$ and $$r >>>a$$. The net force on the free charge $$-q$$ and net torque on it about $$O$$ at the instant shown are respectively.

($$p=2 a Q$$ is the dipole moment)

A uniform electric field vector $$\mathbf{E}$$ exists along horizontal direction as shown. The electric potential at $$A$$ is $$V_A$$. A small point charge $$q$$ is slowly taken from $$A$$ to $$B$$ along the curved path as shown. The potential energy of the charge when it is at point $$B$$ is

A cubical Gaussian surface has side of length $$a=10 \mathrm{~cm}$$. Electric field lines are parallel to $$X$$-axis as shown in figure. The magnitudes of electric fields through surfaces $$A B C D$$ and $$E F G H$$ are $$6 ~\mathrm{kNC}^{-1}$$ and $$9 \mathrm{~kNC}^{-1}$$ respectively. Then, the total charge enclosed by the cube is

[Take, $$\varepsilon_0=9 \times 10^{-12} \mathrm{~Fm}^{-1}$$ ]

Electric field at a distance $$r$$ from an infinitely long uniformly charged straight conductor, having linear charge density $$\lambda$$ is $$E_1$$. Another uniformly charged conductor having same linear charge density $$\lambda$$ is bent into a semicircle of radius $$r$$. The electric field at its centre is $$E_2$$. Then

A tiny spherical oil drop carrying a net charge $$q$$ is balanced in still air, with a vertical uniform electric field of strength $$\frac{81}{7} \pi \times 10^5 \mathrm{~V} / \mathrm{m}$$. When the field is switched OFF, the drop is observed to fall with terminal velocity $$2 \times 10^{-3} \mathrm{~ms}^{-1}$$. Here $$g=9.8 \mathrm{~m} / \mathrm{s}^2$$, viscosity of air is $$1.8 \times 10^{-5} \mathrm{Ns} / \mathrm{m}^2$$ and density of oil is $$900 \mathrm{~kg} \mathrm{~m}^{-3}$$. The magnitude of $$q$$ is

Four charges $$+q_1+2 q_1+q$$ and $$-2 q$$ are placed at the corners of a square $$A B C D$$ respectively. The force on a unit positive charge kept at the centre $$O$$ is

An electric dipole with dipole moment $$4 \times 10^{-9} \mathrm{C}-\mathrm{m}$$ is aligned at $$30^{\circ}$$ with the direction of a uniform electric field of magnitude $$5 \times 10^4 \mathrm{NC}^{-1}$$, the magnitude of the torque acting on the dipole is

A charged particle of mass $$m$$ and charge $$q$$ is released from rest in an uniform electric field E. Neglecting the effect of gravity, the kinetic energy of the charged particle after $$t$$ seconds is

The electric field and the potential of an electric dipole vary with distance $$r$$ as

Two tiny spheres carrying charges $$1.8 \mu \mathrm{C}$$ and $$2.8 \mu \mathrm{C}$$ are located at $$40 \mathrm{~cm}$$ apart. The potential at the mid - point of the line joining the two charges is

Electric field due to infinite, straight uniformly charged wire varies with distance $$r$$ as

A $$2 \mathrm{~g}$$ object, located in a region of uniform electric field $$\mathrm{E}=\left(300 \mathrm{NC}^{-1}\right) \hat{\mathbf{i}}$$ carries a charge $$Q$$. The object released from rest at $$x=0$$, has a kinetic energy of $$0.12 \mathrm{~J}$$ at $$x=0.5 \mathrm{~m}$$. Then, $$Q$$ is

Which of the following statements is false in the case of polar molecules?

A point charge $$q$$ is placed at the corner of a cube of side $$a$$ as shown in the figure. What is the electric flux through the face $$A B C D$$ ?

The electric field lines on the left have twice the separation on those on the right as shown in figure. If the magnitude of the field at $$A$$ is $$40 \mathrm{~Vm}^{-1}$$, what is the force on $$20 \mu \mathrm{C}$$ charge kept at $$B$$ ?

An infinitely long thin straight wire has uniform charge density of $$\frac{1}{4} \times 10^{-2} \mathrm{~cm}^{-1}$$. What is the magnitude of electric field at a distance $$20 \mathrm{~cm}$$ from the axis of the wire?

A dipole moment $$p$$ and moment of inertia $$I$$ is placed in a uniform electric field $$\mathbf{E}$$. If it is displaced slightly from its stable equilibrium position, the period of oscillation of dipole is

Figure shows three points $$A, B$$ and $$C$$ in a region of uniform electric field $$\mathbf{E}$$. The line $$A B$$ is perpendicular and $$B C$$ is parallel to the field lines. Then, which of the following holds good ? ($$V_A, V_B$$ and $$V_C$$ represent the electric potential at points $$A, B$$ and $$C$$, respectively)

When a soap bubble is charged?

Two metal plates are separated by $$2 \mathrm{~cm}$$. The potentials of the plates are $$-10 \mathrm{~V}$$ and $$+30 \mathrm{~V}$$. The electric field between the two plates is

Two protons are kept at a separation of $$10 \mathrm{~nm}$$. Let $$F_n$$ and $$F_e$$ be the nuclear force and the electrostatic force between them

A certain charge $$2 Q$$ is divided at first into two parts $$q_1$$ and $$q_2$$. Later the charges are placed at a certain distance. If the force of interaction between two chagrges is maximum then $$\frac{Q}{q_1}$$ is

A particle of mass $$m$$ and charge $$q$$ is placed at rest in uniform electric field $$E$$ and then released. The kinetic energy attained by the particle after moving a distance $$y$$ is

An electric dipole is kept in non-uniform electric field. It generally experiences

The figure gives the electric potential $$V$$ as a function of distance through four regions on $$x$$-axis. Which of the following is true for the magnitude of the electric field $$E$$ in these regions?

A system of two charges separated by a certain distance apart stores electrical potential energy. If the distance between them is increased, the potential energy of the system