List of top Physics Questions

Which of the following processes is reversible?
In the reaction \(^2_1H+^3_1H\) \(\rightarrow\) \(^4_2He+^1_0n,\) if the binding energies of \(^2_1H\), \(^3_1H\) and \(^4_2He\) are respectively a, b and c (in MeV), then the energy (in MeV) released in this reaction is:
A photosensitive metallic surface has work function, hv0. If photons of energy 2hv0 fall on this surface, the electrons come out with a maximum velocity of 4x106 m/s. When the photon energy is increased to 5hv0, then maximum velocity of photoelectrons will be:
The work functions for metals A,B and C are respectively 1.92 eV, 2.0 eV and 5 eV. According to Einstein's equation, the metals which will emit photoelectrons for a radiation of wavelength 4100 Å is/are:

A photon collides with a stationary hydrogen atom in the ground state inelastically. The energy of the colliding photon is 10.2 eV. After a time interval of the order of microseconds, another photon collides with the same hydrogen atom inelastically with an energy of 15 eV. What will be observed by the detector?

If the angle between the vectors $ \overrightarrow{A}$ and $ \overrightarrow{B}$ is $\theta, $ the value of the product $ ( \overrightarrow{B} \times \overrightarrow{A}) \cdot \overrightarrow{A}$ is equal to
A very long straight wire carries a current $l$. At the instant when a charge +Q at point P has velocity $\overrightarrow{v}$, as shown, the force on the charge is
A particle moves along Y-axis in such a way that its $ y- $ coordinate varies with time $ t $ according to the relation $ y=3+5t+7{{t}^{2}}. $ The initial velocity and acceleration of the particle are respectively:
In series L-C-R circuit, the capacitance is changed from C to 2C. The inductance should be changed from L to ... to obtain same resonance frequency.
By keeping moment of inertia of a body constant, if we double the time period, then angular momentum of body

The displacement x of a particle varies with time t as \(x=ae^{-  \alpha t} + be ^{\beta t}\), where \(a,b,\) \(\alpha\) and \(\beta\) are positive constants. The velocity of the particle will:

The path difference produced by two waves is 3.75 $\mu$m and the wavelength is 5000 $\mathring {A}$. The point is
In a circuit, L,C and R are connected in series with an alternating voltage source of frequency f. The current leads the voltage by 45°.The value of C is:
As a result of change in the magnetic flux linked to the closed loop as shown in the figure, an e.m.f. V volt is induced in the loop. The work done (joule) in taking a charge Q coulomb once along the loop is
A point source emits sound equally in all directions in a non-absorbing medium. Two points P and Q are at distances of 2 m and 3 m respectively from the source. The ratio of the intensities of the waves at P and Q is
The simple pendulum acts as second's pendulum on earth. Its time on a planet, whose mass and diameter are twice that of earth is
A ball is thrown vertically upward. It has a speed of 10m/s when it has reached one half of its maximum height. How high does the ball rise?(Taking g=10 m/s2)
A tuning fork arrangement (pair) produces 4 beats/sec with one fork of frequency 288 .cps. A little wax is placed on the unknown fork and it then produces 2 beats/sec. The frequency of the unknown folk is:
In the nuclear reaction, ${ }_{72} X^{180} {->[-\alpha]} Y {->[-\beta]} Z {->[-\alpha]} A {->[-\gamma]} P$ the atomic mass and atomic number of $P$ are, respectively
If the magnetic dipole moment of an atom of diamagnetic material, paramagnetic material and ferromagnetic material are denoted ny $\mu_d, \mu_p$ and $\mu_f$ respectively, then
The displacement x of a particle varies with time t as $x = ae^{-\alpha t}+be^{\beta t}$ where a, b, $\alpha$ and $\beta$ are positive constants. The velocity of the particle will
Escape velocity for 'a projectile at Earth's surface is v,. A body is projected from earth's surface with velocity $2v_e$. The velocity of the body when it is at infinite distance from the centre of the Earth is
If the length of rod $A$ is $ 3.25\pm 0.01\,cm $ and that of $B$ is $ 4.19\pm 0.01\,cm, $ then the rod $B$ is longer than rod $A$ by
For protecting a sensitive equipment from external magnetic field, it should be
Petrol engine does the work during