List of top Physics Questions

In a pure semiconductor at thermal equilibrium

Pick out the wrong statement about Bohr atom model

A screw gauge has a pitch of 0.1 mm and 100 divisions on its circular scale. When its both jaws touch, the fifth division of its circular scale coincides with zero. When a sphere is placed between the jaws, the reading of the linear scale is 5 mm and the 50th division of the circular scale coincides with zero of the main scale. Find the diameter of the sphere.
A Carnot engine works between \(600\,\text{K}\) and \(300\,\text{K}\). Find its efficiency.

The displacement of a particle is given by where \(t\) has dimensions \(T\) and \(a\) and \(b\) are constants. The dimensions of \(b\) are:

If the stopping potential in a photoelectric experiment is measured to be 1.82 V, the maximum speed of the emitted electrons, in ms\(^{-1}\), is
(mass of the electron = \(9.1\times10^{-31}\) kg)}
If an EM wave travels in a medium with \(\varepsilon_r = 4\), \(\mu_r = 1\), its speed (in ms\(^{-1}\)) in terms of \(c\) (\(c =\) velocity of light in free space) is}
Light of wavelength 500 nm falls on a single slit of width 0.1 mm. The angular position of the first minimum is}
An object is placed at 30 cm from a convex lens of focal length 20 cm. If the object is moved towards the lens by 5 cm, then the image is shifted by}
A particle executes SHM with a time period \(T\). If its maximum acceleration is doubled keeping the amplitude constant, its new time period is}
A string of length \(L\) fixed at both ends vibrates in third harmonic. The distance between consecutive nodes is}
If a thin uniform circular ring and a thin uniform circular disc have the same mass and radius, then the ratio of their moments of inertia about their central axes normal to their planes is}
Two particles of masses \(m\) and \(2m\) kept 1 m apart are attracted to each other by gravitational force. The acceleration of their centre of mass is \((G = \text{gravitational constant})\)}
The power of a motor pump delivering water at a constant speed through a hose of radius \(r\) is \(P\). If the radius of the hose is doubled, then the power of the pump becomes}
A particle of mass \(m\) tied to a string of length \(r\) is whirled in a vertical circle. Its minimum speed at the bottom is}
0.2 kg ball strikes a wall with velocity \(10\,ms^{-1}\) and rebounds with \(8\,ms^{-1}\). The impulse delivered by the ball is}
A particle moves under a force \(F = 3x^2\) N. The work done by the force on the particle in displacing it from \(x=0\) to \(x=2\text{ m}\) is}
Two particles A and B at rest initially, start to move simultaneously along the same straight line, A with constant velocity \(5\,ms^{-1}\) and B with constant acceleration \(2\,ms^{-2}\). Then the time after which B overtakes A is}
The velocity (\(v\)) – time (\(t\)) graph of a particle cuts the time axis, then the particle}
A $250$ watt bulb emits monochromatic light of wavelength $198.78$ nm. How many photons are emitted by the bulb per second? \ (Planck’s constant = $6.626 \times 10^{-34}$ J s and velocity of light = $3 \times 10^8$ ms$^{-1}$)
The logic gate that performs the operation of an inverter is
The ground state energy of hydrogen atom is -13.6 eV. The energy of the second excited state is
The focal length of a plane mirror is
In an n-p-n transistor, the majority charge carriers in the emitter are
Ripple frequency in full-wave rectifier of input frequency $f$ is: