List of top Physics Questions

The frequency of a tuning fork P is 1.5% more than the frequency of tuning fork Q and the frequency of another tuning fork R is 2.5% less than the frequency of tuning fork Q. If 8 beats are produced per second when P and R are vibrated together, then the frequency of tuning fork R is

The equation for the displacement (x) of a particle executing simple harmonic motion is $x=18\sin\left(2\pi t+\frac{\pi}{2}\right)$ cm, where 't' is time in second. The minimum time after $t=0$ when the velocity of the particle becomes maximum is

The permeability of the material of the core used in a solenoid of length 1.4 m, radius 7 cm having $10^3$ turns and a self-inductance of 2.2 H is

A steel wire of initial length 149 cm extends by 0.5 cm when a tension of 50 N is applied along its length. If an additional tension of 100 N is applied to the same wire, then the final length of the wire is

Keeping the number of gas molecules per unit volume as constant, if the radius of the gas molecule is doubled, then the mean free path of the gas molecules

The ratio of the rate of disintegration and the initial number of nuclei of a radioactive substance is $0.25~hour^{-1}$. The time taken (in hours) for the number of nuclei of this substance to become $\frac{1}{\sqrt{e}}$ times the initial number of nuclei is}

In the band structure of n-type semiconductor , the free electrons donated by impurity atoms occupy energy levels in

An electron in the hydrogen atom jumps from \(n^{th}\) energy state to the ground state. The wavelength so emitted illuminates a photosensitive material having work function \(2.65\) eV. If the maximum kinetic energy of the emitted photoelectrons is \(10.1\) eV, then the value of '\(n\)' is

The output Y of the following digital logic circuit will be '1' (one) for the inputs

Two identical photocathodes receive light of frequencies \(n_1\) and \(n_2\). If the velocities of the emitted photoelectrons of mass m are \(V_1\) and \(V_2\) respectively, then (\(h\) = Planck's constant)

The proton and \(α\) - particle are accelerated through same potential difference. Then the ratio of the de-Broglie wavelength of proton and \(α\) - particle is (mass of \(α\)-particle is \(4\) times mass of proton, charge of \(α\)-particle is \(2\) times charge of proton)

The angular momentum of an electron in Bohr's hydrogen atom having energy \((-0.544)\) eV is
(\(h\) = Planck's constant)

In a common emitter transistor amplifier, AC current gain is \(65\), the load resistance is \(5400\,\Omega\) and input resistance of the transistor is \(450\,\Omega\). The voltage gain is

In an interference experiment, the \(m^{th}\) bright fringe for light of wavelength \(λ_1\) coincides with the \(n^{th}\) dark fringe for light of wavelength \(λ_2\) . The ratio \(\frac{λ_2}{λ_1}\) is

The prism has refracting angle A. The second refracting surface of the prism is silvered. Light ray falling on first refracting surface with angle of incidence \(2A\), reaches the second surface and returns back through same path due to reflection at the silvered surface. The refractive index of the material of prism is

Light of wavelength \(580\) nm is incident normally on a slit of width '\(a\)'. The distance between slit and screen is \(2.5\) m and the distance of the second order maximum from the centre of the screen is \(14.5\) mm in a diffraction pattern. The value of '\(a\)' is

When an inductance '\(L\)' and resistor '\(R\)' are connected in series to \(25\)V, \(50\) Hz supply, a current of \(0.5\) A flows in the circuit. The current lags behind in phase from applied voltage by \((\frac{π}{3})\) radian. The value of R is \((cos60^{\circ} = \frac{1}{2})\)

In the circuit shown charge q varies with time t as \(q = t^2-5\), where q is in coulomb and t is in second. At time \(t = 3\) second, voltage \(V_{AB}\) in volt will be

In a biprism experiment, the distance between \(4^{th}\) and \(13^{th}\) bright band on the same side is '\(y\)' when light of wavelength \(6000\) Å is used. For a light of wavelength '\(λ\)' the distance between \(6^{th}\) and \(16^{th}\) bright band on the same side is again '\(y\)'. The value of '\(λ\)' in Å units is

A square loop ABCD of side L carrying a current \(I_1\) is placed at a distance \((L/3)\) from a conductor coplaner with a straight conductor XY carrying current \(I_2\) as shown in figure. The net force on the loop will be (\(μ_0\) = magnetic permeability)

The self inductance of an air-core inductor (solenoid) is \(0.03\) mH. By introducing an iron core into inductor the self-inductance increases to \(30\) mH. The relative permeability of the core used is

A long solenoid carrying a current produces a magnetic field '\(B\)' along its axis. If the currunt is tripled and the number of turns per cm is halved then new value of magnetic field will be

Which graph shows the correct variation of r.m.s. current '\(i\)' with frequency '\(f\)' of a.c. in case of series resonant circuit ?

A coil of effective area \(3\) m\(^2\) is placed at right angles to a magnetic field of induction \(0.05\) Wb/m\(^2\). If the field is decreased to \(20\%\) of its original value in \(10\) second, the e.m.f. induced in the coil will be

In a series LCR circuit, the voltage across R is \(100\) V, \(R = 1\,\text{K}\,\Omega\) and \(C = 2\,μ\text{F}\). The angular frequency \(ω\) is \(200\) rad s\(^{-1}\). At resonance, the voltage across '\(L\)' is