Question Bank Directory

The equivalent capacitance of the arrangement shown in the figure is:

The minimum energy required to launch a satellite of mass $m$ from the surface of the earth of mass $M$ and radius $R$ in a circular orbit at an altitude of $2R$ from the surface of the earth is:

The magnetic field in a plane electromagnetic wave is given by: $B_y = 2 \times 10^{-7} \sin(\pi \times 10^3x + 3\pi \times 10^{11}t) \text{ T}$. The wavelength is:

An electric dipole of moment $\vec{p}$ is lying along a uniform electric field $\vec{E}$. The work done in rotating the dipole by $90^{\circ}$ is:

In a region, the potential is represented by V(x,y,z) = 6x - 8xy - 8y + 6yz, where V is in volts and x, y, z are in meters. The electric force experienced by a charge of 2 coulomb situated at point (1, 1, 1) is

Two condensers, one of capacity $C$ and the other of capacity $C/2$ are connected to a $V$ volt battery, as shown in the figure. The energy stored in the capacitors when both condensers are fully charged will be:

Air is pushed carefully into a soap bubble of radius $r$ to double its radius. If the surface tension of the soap solution is $T$, then the work done in the process is:

The capacitance of a parallel plate capacitor with air as a medium is $6 \, \mu\text{F}$. With the introduction of a dielectric medium, the capacitance becomes $30 \, \mu\text{F}$. The permittivity of the medium is: $(\varepsilon_0=8.85 \times 10^{-12} \text{ C}^2 \text{ N}^{-1} \text{ m}^{-2})$

The wettability of a surface by a liquid depends primarily on:

The net magnetic flux through any closed surface is:

A fluid of density $\rho$ is flowing in a pipe of varying cross-sectional area as shown in the figure. Bernoulli's equation for the motion becomes:

Angular momentum of a body is defined as the product of:

A capacitor of capacitance C = 900 pF is charged fully by a 100 V battery B as shown in Figure (a). Then it is disconnected from the battery and connected to another uncharged capacitor of capacitance C = 900 pF as shown in Figure (b). The electrostatic energy stored by the system (b) is:

A body weighing $100 \text{ N}$ on the surface of the Earth weighs $x \text{ kg m s}^{-2}$ at a height $\frac{1}{9}R_E$ above the surface of Earth. The value of $x$ is: (take $g=10 \text{ m s}^{-2}$ at the surface of Earth and $R_E$ is the radius of Earth)

The electric potential at a point (x, y, z) is given by V = -x²y - xz³ + 4. The electric field E at that point is

If the plates of a parallel plate capacitor connected to a battery are moved closer to each other, then: (A) The charge stored in it increases. (B) The energy stored in it decreases. (C) Its capacitance increases. (D) The ratio of charge to its potential remains the same. (E) The product of charge and voltage increases. Choose the most appropriate answer from the options given below:

The distance between the two plates of a parallel plate capacitor is doubled, and the area of each plate is halved. If C is its initial capacitance, its final capacitance is equal to:

Three capacitors, each of capacitance $0.3 \text{ \mu F}$, are connected in parallel. This combination is connected with another capacitor of capacitance $0.1 \text{ \mu F}$ in series. Then the equivalent capacitance of the combination is:

The ratio of escape velocity at the Earth ($v_e$) to the escape velocity at a planet ($v_p$) whose radius and mean density are twice that of the Earth is:

The escape velocity from the Earth's surface is $v$. The escape velocity from the surface of another planet having a radius, four times that of Earth and the same mass density is: