List of top Physics Questions

If the angular momentum of a planet of mass $m$, moving around the Sun in a circular orbit is $L$, about the center of the Sun, its areal velocity is :

A particle undergoing simple harmonic motion has time dependent displacement given by $x(t) = A \sin \frac{\pi t}{90}$. The ratio of kinetic to potential energy of this particle at $t\, =\, 210\, s$ will be :

A rod of mass $'M'$ and length $'2L'$ is suspended at its middle by a wire. It exhibits torsional oscillations; If two masses each of $'m'$ are attached at distance $'L/2'$ from its centre on both sides, it reduces the oscillation frequency by $20\%$. The value of ratio $m/M$ is close to :

A simple pendulum, made of a string of length $l$ and a bob of mass m, is released from a small angle $\theta_0$. It strikes a block of mass $M$, kept on a horizontal surface at its lowest point of oscillations, elastically. It bounces back and goes up to an angle $\theta_1$. Then M is given by :

A simple pendulum of length $1\, m$ is oscillating with an angular frequency $10\, rad/s$. The support of the pendulum starts oscillating up and down with a small angular frequency of $1 \,rad/s$ and an amplitude of $10^{-2} \; m$. The relative change in the angular frequency of the pendulum is best given by :

A proton and an $\alpha$-particle (with their masses in the ratio of $1 : 4$ and charges in the ratio of $1 : 2$) are accelerated from rest through a potential difference $V$. If a uniform magnetic field (B) is set up perpendicular to their velocities, the ratio of the radii $r_p : r_\alpha$ of the circular paths described by them will be :

In a flask of 'V' litres, 0.2 moles of O₂, 0.4 moles of N₂, 0.1 moles of NH₃ and 0.3 moles of He gases are present at 27^oC. If total pressure exerted by these non-reaching gases is 1 atm, the partial pressure exerted by N₂ gas is

The density of O₂ is 16 at NTP. At what temperature its density will be 14?consider that the pressure remain the constant at

A piece of an ancient wooden boat shows an activity of C¹⁴ of 3.9 disintegrations per minute per gm of carbon. Estimate the age of the boat, if the half life of C¹⁴ is 5.568 years. Assume that the activity of fresh carbon -14 is 15.6 dpm.gm

The most widely used rectifier is

Which of the following transitions in hydrogen atoms emit photons of highest frequency?

X-rays of wavelength 1.14 A in the first order reflection from a crystal, were reflected at an angle of 30^o.
The inter planar distance in the crystal is (Sin 30^ois 0.5)

Connecting a lead from the negative to the positive of a battery will produce

When boron \(_{5}B^{10}\) is bombarded by neutron, alpha particles are emitted. The resulting nucleus has the mass number.

The unit of relative permittivity is

An electron in Bohr's hydrogen atom has an energy of -3.4 eV. The angular momentum of the electron is:

If ionising energy of H atom is 13.6eV, then the second ionising energy of He should be

The frequency of the charged particle circular at right angles to a uniform magnetic field does not depend upon the

Radiation of two photons having energies twice and five times the work function of a metal are incident successively on the metal surface.Find out the ratio of maximum velocity of photo electrons emitted in the two cases.

The ratio of the radii of the nuclei \(_{13}Al^{27}\) and \(_{52}Te^{125}\) is approximately

A pair of coil has a mutual inductance of 2 H, if the current in the primary changes from 10 A to zero in 0.1 S, the induced emf in the secondary will be

Huygen's principle of secondary waves is used to

How many orders will be visible if the wavelength of the incident radiation is 5000 and the number of lines on the grating is 2620 in one inch?

If the door of a refrigerator in a room is kept open, the temperature of room will be