List of top Physics Questions

The unit of permittivity of free space, $ {{\varepsilon }_{0}}, $ is

300 J of work is done in sliding a 2 kg block up an inclined plane of height 10 m. Taking $ g=10\,m/{{s}^{2}}, $ the work done against friction is

The tension in vibrating streched piano wire is 10 N. To double the frequency, the tension in wire must be

Dopplers effect in sound takes place when source and observer arc

The threshold wavelength for a metal having work function $ W_0 $ is $\lambda_0 $. What is the threshold wavelength for a metal whose work function is $ \frac{ W_0 }{ 2 } $ ?

the power factor of a series L-C-R circuit when at resonance is

The phase difference between the instantaneous velocity and acceleration of a particle executing simple harmonic motion is

The period of oscillation of a simple pendulum of constant length al surface of the earth is $T$. Its time period inside a mine will be

The peak voltage in the output of a half-wave diode rectifier fed with a sinusoidal signal without filter is $10\, V$. The DC component of the output voltage is

The moment of inertia of a thin uniform circular disc about one of the diameters is $l$. Its moment of inertia about an axis perpendicular to the plane of the disc and passing through its centre is

The maximum intensity of fringes in Youngs experiment is $I$. If one of the slit is closed then the intensity at that place becomes $I_{0}$ . Which of the following relation is true?

The limiting friction is

The intensity of sound increases at night due to

The driver of a car travelling at velocity $v$ suddenly sees a broad wall in front of him at a distance $d$. He should

The displacement of an object attached to a spring and executing simple harmonic motion is given by $x = 2 ??10^{-2}\, cos\, \pi t$ metres. The time at which the maximum speed first occurs is

The dimensions of $\frac{e^{2}}{4 \pi \varepsilon_{0} h c'}$, where $e, \varepsilon_{0}, h$ and $c$ and $c$ are electronic charge, electric permittivity Planck's constant and velocity of light in vacuum respectively

The dimensions of universal gravitational constant are

The degrees of freedom of a molecule of a triatomic gas are

The capacity of an isolated conducting sphere of radius $R$ is proportional to

On introducing a thin film in the path of one of the two interfering beams, the central fringe will shift by one fringe width. If $ \mu =1.5, $ the thickness of the film is (wavelength of monochromatic light is $ \lambda $ )

Moment of inertia of ring about its diameter is $ I. $ Then, moment of inertia about an axis passing through centre perpendicular to its plane is

Mass spectrometric analysis of potassium and argon atoms in a Moon rock sample shows that the ratio of the number of (stable) ${ }^{40} Ar$ atoms present to the number of (radioactive) ${ }^{40} K$ atoms is $10.3$. Assume that all the argon atoms were produced by the decay of potassium atoms, with a half-life of $1.25 \times 10^{9} yr$. How old is the rock?

Infrared radiations are detected by

In an $L-R$ circuit, time constant is that time in which current grows from zero to the value where $ I_{0}$ is steady state current.

If the half-life of any sample of radioactive substance is $4$ days, then the fraction of sample will remain undecayed after $2$ days, will be?