List of top Physics Questions

The change in the gravitational potential energy when a body of mass $m$ is raised to a height $nR$ above the surface of the earth is (here $R$ is the radius of the earth)
Two point coherent sources of light S and S are placed on a line as shown. P and Q are two points on that line. If at point P maximum intensity is observed then maximum intensity should also be observed at In the figure of assertion the distance $\left|S_{1}P-S_{2}P\right|$ is equal to distance $\left|S_{2}Q-S_{1}Q\right|$.
Pseudo force is an imaginary force which is recognised only by a non-inertial observer to explain the physical situation according to Newton?? laws. Pseudo force has no physical origin, i.e., it is not caused by one of the basic interactions in nature. It does not exist in the action-reaction pair.
An n-type semiconductor has a large number of electrons but still it is electrically neutral. An n-type semiconductor is obtained by doping an intrinsic semiconductor with a pentavalent impurity.
A solid sphere is rolling on a rough horizontal surface. Acceleration of contact point is zero. A solid sphere can roll on the smooth surface.
A transformer with efficiency 80% works at $4\, kW$ and $100\, V$. If the secondary voltage is $200\,V$, then the primary and secondary currents are respectively
Two concentric conducting thin spherical shells $A$ and $B$ having radii $r _{ A }$ and $r _{ B }\left( r _{ B }> r _{ A }\right)$ are charged to $Q _{ A }$ and $- Q _{ B }\left(\left| Q _{ B }\right|>\left| Q _{ A }\right|\right)$. The electrical field along a line passing through the centre is
A neutron in a nuclear reactor collides head on elastically with the nucleus of a carbon atom initially at rest. The fraction of kinetic energy transferred from the neutron to the carbon atom is
A circular coil of radius $10 \,cm$, $500\, turns$ and resistance $2 \,\Omega$ is placed with its plane perpendicular to the horizontal component of the earth?s magnetic field. It is rotated about its vertical diameter through 180$^{\circ}$ in $0.25\, s$. The current induced in the coil is (Horizontal component of the earth?s magnetic field at that place is $3.0 \times 10^{-5}$ T)
A wheel starts rotating from rest at time t = 0 with a angular acceleration of 50 radians/s. The angular acceleration ($\alpha$) decreases to zero value after 5 seconds. During this interval, $\alpha$ varies according to the equation $\alpha=\alpha_{0}\left(1-\frac{t}{5}\right)$ The angular velocity at t = 5 s will be
In an LCR circuit as shown in figure, both switches are open initially. Now switch S is closed, S kept open. (q is charge on the capacitor and $\tau$ = RC is capacitive time constant). Which of the following statement is correct?
Two chamber containing $m_1$ and $m_2$ grams of a gas at pressures $P_1$ and $P_2$ respectively are put in communication with each other, temperature remaining constant. The common pressure reached will be
Two circularly shaped linear polarisers are placed coaxially. The transmission axis of the first polariser is at $30^{\circ}$ from the vertical while the second one is at $60^{\circ}$, both in the clockwise sense. If an unpolarised beam of light of intensity $I=20 \,W / m ^{2}$ is incident on this pair of polarisers, then the intensities $I_{1}$ and $I_{2}$ transmitted by the first and second polarisers
Consider a bowl filled with water on which some black pepper powder have been sprinkled uniformly. Now, a drop of liquid soap is added at the centre of the surface of water. The picture of the surface immediately after this will look like
What is the voltage across an ideal p-n junction diode for shown circuit ?
Gravitational force acts on a particle due to fixed uniform solid sphere. Neglect other forces. Then particle
An object of mass 26 kg floats in air and it is in equilibrium state. Air density is $1.3 \,kg/m^3$ . The volume of the object is :
Two very long, straight, parallel wires carry steady currents $ I$ and $-I$ respectively. The distance between the wires is $d$. At a certain instant of time, a point charge $q$ is at a point equidistant from the two wires, in the plane of the wires. Its instantaneous velocity $v$ perpendicular to this plane. The magnitude of the force due to the magnetic field acting on the charge at this instant is
Specific conductance of o.1 \,M \,HA is $3 \cdot 75 \times 10^{-4} \,ohm ^{-1} \, cm ^{-1}$. Find the dissociation constant $K _{ a }$ of $HA$, if $\lambda_{\infty}( HA )=250 \, ohm ^{-1} \, cm ^{2} \,mol ^{-1}:$
In the formula $X=3 Y Z^{2}, X$ and $Z$ have dimensions of capacitance and magnetic induction respectively. The dimensions of $Y$ in $MKSA$ system are :
In Fraunhofer diffraction pattern, slit width is $0.2\, mm$ and screen is at $2 \,m$ away from the lens. If wavelength of light used is $5000 \, \mathring A $ then the distance between the first minimum on either side of the central maximum is ($\theta$ is small and measured in radian)
Consider an expanding sphere of instantaneous radius
A flat plate is moving normal to its plane through a gas under the action of a constant force $F$. The gas is kept at a very low pressure. The speed of the plate $v$ is much less than the average speed $u$ of the gas molecules. Which of the following options is/are true?
A converging lens has a focal length of $ 0.12\, m $ . To get an image of unit magnification the object should be placed at what distance from the converging lens?
A bird flies at an angle of $ 60^{\circ} $ to the horizontal. Its horizontal component of velocity is $ 10\, m\, s ^{-1} $ . Find the vertical component of velocity in $ m s ^{-1} $ .