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A parallel plate air capacitor of capacitance C is connected to a cell of emf V and then disconnected from it. A dielectric slab of dielectric constant K, which can just fill the air gap of the capacitor, is now inserted in it. Which of the following is incorrect?
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 diagrams below show regions of equipotentials. A positive charge is moved from A to B in each diagram. Then:
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: $(\varepsilon_0=8.85 \times 10^{-12} \text{ C}^2 \text{ N}^{-1} \text{ m}^{-2})$
A dielectric slab of dielectric constant 3 having the same area of cross-section as that of a parallel plate capacitor but of thickness 3/4th of the separation of the plates is inserted into the capacitor. The ratio of potential difference across the plates without dielectric to that with dielectric is:
The wettability of a surface by a liquid depends primarily on:
The net magnetic flux through any closed surface is:
Two metallic spheres of radii 1 cm and 3 cm are given charges of -1×10⁻² C and 5×10⁻² C, respectively. If these are connected by a conducting wire, the final charge on the bigger sphere is:
The molar specific heats of an ideal gas at constant pressure and volume are denoted by $C_P$ and $C_V$ respectively. If $\gamma = C_P/C_V$ and $R$ is the universal gas constant, then $C_V$ is equal to:
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:
Match List-I with List-II: **List-I** (a) Gravitational constant (G) (b) Gravitational potential energy (c) Gravitational potential (d) Gravitational intensity **List-II** (i) $[L^2 T^{-2}]$ (ii) $[M^{-1} L^3 T^{-2}]$ (iii) $[LT^{-2}]$ (iv) $[ML^2 T^{-2}]$ Choose the correct answer from the options given below:
Angular momentum of a body is defined as the product of:
A parallel plate capacitor with cross-sectional area A and separation d has air between the plates. An insulating slab of the same area but the thickness of d/2 is inserted between the plates as shown in the figure, having a dielectric constant, K=4. The ratio of the new capacitance to its original capacitance will be:
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:
The root-mean-square speed of hydrogen molecules at 300 K is 1930 m/s. Then the root mean square speed of oxygen molecules at 900 K will be:
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)
If potential (in volts) in a region is expressed as V(x,y,z) = 6xy - y + 2yz, the electric field (in N/C) at point (1,1,0) is
The electric potential at a point (x, y, z) is given by V = -x²y - xz³ + 4. The electric field E at that point is
A thin spherical shell is charged by some source. The potential difference between the two points C and P (in V) shown in the figure is: (Take 1/4πε₀ = 9 × 10⁹ SI units)
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: