List of top Physics Questions

A man of mass \(m\) starts falling towards a planet of mass \(M\) and radius \(R\). As he reaches near to the surface, he realizes that he will pass through a small hole in the planet. As he enters the hole, he sees that the planet is really made of two pieces: a spherical shell of negligible thickness of mass \(3M/4\) and a point mass \(M/4\) at the centre. Change in the force of gravity experienced by the man is

In a mixture of gases, the average number of degrees of freedom per molecule is 6. The rms speed of the molecule of the gas is \(c\), then the velocity of sound in the gas is

An ideal spring with spring-constant \(k\) is hung from the ceiling and a mass \(M\) is attached to its lower end. The mass is released with the spring initially unstretched. Then the maximum extension in the spring is

A rigid dipole undergoes a simple harmonic motion about its centre in the presence of an electric field $\vec{E}_1 = E_0 \hat{x}$. If another electric field $\vec{E}_2 = 2E_0 (\hat{y} + \hat{z})$ is introduced to the system, what will be the percentage change in the frequency of the oscillation (approximate)?

In a Young's Double Slit Experiment, find the fringe width if the distance between slits is doubled and the screen distance is halved.

Determine the energy of a photon in eV if its wavelength is \( 4000\ \text{\AA} \).

Find the ratio of the de Broglie wavelengths of a proton and an alpha particle accelerated through the same potential difference.

A capillary tube of radius \( r \) is dipped in water; find the height \( h \) to which water rises if the surface tension is \( T \).

Calculate the moment of inertia of a uniform ring of mass \( M \) and radius \( R \) about a tangent in its own plane.

Find the acceleration of a \(2\) kg block acted upon by a net force of \(10\) N.

A car starts from rest and accelerates uniformly at \(3\ \text{m/s}^2\); determine its velocity after \(5\) seconds.

Find the ratio of fundamental frequencies \( f_1/f_2 \) for a pipe open at both ends when \( \frac{1}{3} \) of its length is later submerged in water.

Calculate the percentage increase in apparent frequency for an observer moving towards a stationary sound source with \( \frac{1}{5} \)th the velocity of sound.

Determine the ratio of the speed of sound in Oxygen to that in Hydrogen at the same temperature.

Find the equivalent resistance between two opposite corners of a cube made of wires, each having resistance \(R\).

Calculate the de-Broglie wavelength of an electron accelerated through a potential difference of \(100\text{ V}\).

A gas having \(\gamma = \frac{5}{2}\) and volume 360 cc is suddenly compressed to 90 cc. If the initial pressure of the gas is \(P\), find the final pressure.

Find the heat energy that must be supplied to 14 g of nitrogen at room temperature to raise its temperature by \(48^\circ\text{C}\) at constant pressure. (Molecular weight of nitrogen = 28; \(R\) is the gas constant; \(C_p = \frac{7}{2}R\) for a diatomic gas.)

A particle starts oscillating simple harmonically from its mean position with time period \(T\). At time \(t = \frac{T}{6}\), find the ratio of potential energy to kinetic energy of the particle.

An air column is of length 17 cm. Find the ratio of the frequency of the 5th overtone when the column is closed at one end to that when it is open at both ends. (Speed of sound in air = 340 m/s.)

A river of width 200 m is flowing from west to east with a speed of 18 km/h. A boat, moving with speed of 36 km/h in still water, is made to travel one-round trip (bank to bank of the river). Minimum time taken by the boat for this journey and also the displacement along the river bank are _________ and _________} respectively.

Two blocks of masses 2 kg and 1 kg respectively are tied to the ends of a string which passes over a light frictionless pulley as shown in the figure below. The masses are held at rest at the same horizontal level and then released. The distance traversed by the centre of mass in 2 s is _______ m.

A point light source emits E.M. waves in free space. A detector, placed at a distance of $L$ m, measures the intensity as $I_0$. The detector is now shifted to another location on the same spherical surface ensuring the angle between original location and new location as $45^{\circ}$. The measured intensity at new location will be ————.

The energy released when $\frac{7}{17.13} \text{ kg}$ of ${}^7_3\text{Li}$ is converted into ${}^4_2\text{He}$ by proton bombardment is $\alpha \times 10^{32} \text{ eV}$. The value of $\alpha$ is ____. (Nearest integer)
(Mass of ${}^7_3\text{Li} = 7.0183 \text{ u}$, mass of ${}^4_2\text{He} = 4.004 \text{ u}$, mass of proton $= 1.008 \text{ u}$ and $1 \text{ u} = 931 \text{ MeV}/c^2$ and Avogadro number $= 6.0 \times 10^{23}$)