List of top Physics Questions

The bob of a simple pendulum is a ball full of water, if a fine hole is made in the bottom of the ball, the time period first increases and then decreases. As water flows out of the bob the weight of bob decreases.
The reiation between electric field vector E, the displacement vector D and the polarization vector P for a dielectric placed in electric field E is given by
A charge $Q$ is placed at each of the opposite corners of a square. A charge $q$ is placed at each of the other two corners. If the net electrical force on $Q$ is zero, then the $Q/q $ equals
The surface charge density (in $ Cm^{-2} $ ) of the earth is about
Under the influence of the coulomb field of charge $+\,Q$, a charge $-\,q$ is moving around it in an elliptical orbit. Find out the correct statement(s).
Gausss law is valid for
Figure below show regular haxagons, with charges at the vertices. In which case is the electric field at the centre zero ?
A charge $Q$ is uniformly distributed over a large square plate of copper. The electric field at a point very close to the centre of the plate is 10 $ Vm^{ -1}$. If the copper plate is replaced by a plastic plate of the same geometrical dimensions and carrying the same charge $Q$ uniformly distributed, then the electric field at the point $P$ will be
A pendulum bob of mass $m$ carrying a charge $q$ is at rest with its string making an angle $\theta$ with the vertical in a uniform horizontal electric field $E$. The tension in the string is
Four charges are arranged at the corners of a square as shown in the figure. The direction of electric field at the centre of the square is along
The excess pressure inside a cylindrical drop of liquid or a cylindrical bubble of radius $r$ in a liquid of surface tension $T$ is
The excess pressure inside a spherical drop of water is four times that of another drop. Then their respective mass ratio is
The length of a needle floating on water is 2.5 cm. Calculate the added force (due to surface tension) required to pull the needle out of water. (Surface tension of water $ =7.2\times {{10}^{-2}}N/{{m}^{2}} $ )
A capillary tube of radius r is immersed in water and water rises in it to a height H. Mass of water in the capillary tube is m. If the capillary of radius 2r is taken and dipped in water, the mass of water that will rise in the capillary tube will be
Two charged spheres of radii $R_1 \, and \, R_2$ have equal surface charge density. The ratio of their potential is
A parallel plate air capacitor has a capacitance $C$. When it is half filled with a dielectric of dielectric constant $5$, the percentage increase in the capacitance will be :
Two points $P$ and $Q$ are maintained at the potentials of $10\,V$ and $-4\,V$ respectively. The work done in moving $100$ electrons from $P$ to $Q$ is
Three point charges $ q,\,-2q $ and $ -2q $ are placed at the vertices of an equilateral triangle of side $ a $ . The work done by some external force to increase their separation to $ 2a $ will be
The equivalent capacitance of the circuit will be
What is the energy stored in the capacitor between terminals a and b of the network shown in the figure? (Capacitance of each capacitor C = 1 ??)
Two spherical conductors $B$ and $C$ having equal radii and carrying equal charges in them repel each other with a force $F$ when kept apart at some distance. A third spherical conductor having same radius as that of $B$ but uncharged, is brought in contact with $B$, then brought in contact with $C$ and finally removed away from both. The new force of repulsion between $B$ and $C$ is
The electric potential at a point $(x. y, z)$ is given by $ V = - x^2 y - xz^2 + 4 $ The electric field at that point is
The unit of magnetic moment is
A ball is projected vertically upwards with a certain initial speed. Another ball of the same mass is projected at an angle of $60^{\circ}$ with the vertical with the same initial speed. At highest points of their journey, the ratio of their potential energies will be
The formula for horizontal range of a projectile is $S=\frac{v^{2}\sin ^{2}\theta }{2g}$ where $v$ is initial speed, $ \theta $ angle of inclination and $g$ is acceleration due to gravity. The Wheatstone bridge shown in figure can be used to determine the range if the following arrangement is made