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Two identical capacitors are charged to different potentials, and then they are connected to each other in such a way that the Sum of charges on plates having positive polarity remains constant. Mark the correct statement:

Refer to the circuit shown in Fig. What inputs X and Y will produce a high output at R?

Which
among the curves shown in Fig. 1.35 cannot possibly represent
electrostatic field lines?

(a)

(b)

(c)

(d)

(e)

An electronically driven loudspeaker is placed near the open end of a resonance column apparatus. The length of air column in the tube is 80 cm. The frequency of the loudspeaker can be varied between 20 Hz and 2 kHz. Find the frequencies at which the column will resonate. Speed of sound in air = $320m{s}^{-1}$.

A ball of mass $50\text{g}$ and relative density $0.5$ strikes the surface of water with a velocity of $20\text{m/s}$. It comes to rest at a depth of $2\text{m}$. Find the work done by the resisting force in water.

$($Take, $g=10{\text{m/s}}^2)$

The time period of a pendulum in the elevator that is accelerating at g upward

A point charge$(+10\text{nC})$ is kept at point $P(1,2,3)$ and a test charge is kept at point $Q(3,4,5)$. Find the electric field experienced by the test charge.

$[$Assume distances in metre$]$

A boy playing on the roof of a 10m high building throws a ball with a speed of 10 m/s at an angle of ${30}^{\circ }$ with the horizontal. How far from the throwing point will the ball be at the height of 10 m from the ground $(g=10m/s^2,sin{30}^{\circ }=\frac{1}{2},cos{30}^{\circ }=\frac{\sqrt{3}}{2})$

A point charge $q_1=-5.8\mu \text{C}$ is held stationary at the origin. A second charge $q_2=+4.3\mu \text{C}$ moves from the point $(0.26\text{m},0,0)$ to $(0.38\text{m},0,0)$. Find the workdone by the electric force on $q_2$.

A cylinder has a radius $10\text{cm}$. What height should it be filled with water so that the thrust at its walls is equal to that on its bottom?

Find the magnetic induction at point $\text{O}$ due to the loop of current $i=2\text{A}$ as shown below. The side of square $b=\sqrt{2}\text{cm}$ and radius of the circle is $\pi \text{cm}$.

The electric field between the plates of a parallel plate capacitor of capacitance $2.0\mu \text{F}$ drops to one third of its initial value in $4.4\mu \text{s}$ when the plates are connected by a thin wire. Find the resistance of the wire. $(\ln 3=1.0985)$

Retinal is derived from which of the following?

1. 3.92

A resonance air column of length 20 cm resonates with a tuning fork of frequency

250 Hz. The speed of sound in air is

[AFMC 1999; BHU 2000; CPMT 2001]

In the given circuit the current through Zener Diode is close to:

Which of the following graphs correctly represent the variation of electric field $E$ vs $r$ for a ring, where $r$ represents the distance from the centre of ring along its axis.

In a region of uniform electric field of magnitude $10\text{N/C}$, what will be the energy stored in a sphere of radius $3\text{m}?$

For a convex mirror :

Two gases occupy two containers A and B. The gas in A, of volume $0.10{\text{m}}^3$, exerts a pressure of $1.40\text{MPa}$ and that in B, of volume $0.15{\text{m}}^3$, exerts a pressure of $0.7\text{MPa}$. The two containers are joined by a tube of negligible volume and the gases are allowed to intermingle. Then, if the temperature remains constant, the final pressure in the containers will be $\left(\text{in MPa}\right)$:

Three balls of masses $1kg$, $2kg$ and $3kg$ are attached to three strings of lengths $2m$ each as shown in figure. They are rotated in a horizontal circle with angular speed $\omega =2rad/s$ about point 'O'. Then the value of $T_1+T_2-3T_3$ is

Two identical capacitors 1 and 2 connected in series to a battery as shown in figure. Capacitor 2 contains a dielectric slab of dielectric constant K as shown. If $Q_1$ is the charge on each capacitor before removing the slab and $Q_2$ is the charge on each capacitor after
moving the slab, then the correct relation between $Q_1$ and $Q_2$
is.

The uncertainty for the calculation of the radius of the $1^{st}$ Bohr orbit is $2\%$ for the hydrogen atom. What will be the minimum uncertainty in velocity of an electron in the $1^{st}$ Bohr orbit?



$(h=6.626\times {10}^{–34}\text{J.s},m_e=9.1\times {10}^{–31}\text{kg})$

The effective resistance between points $\text{P}$ and $\text{Q}$ of the electrical circuit shown in the figure is:

One mole of a gas expands with temperature $T$ such that its volume, $V=k{T}^2$, where $k$ is a constant. If the temperature of the gas changes by ${60}^{\circ }C$ then the work done by the gas is