List of top Physics Questions asked in BHU PET

A term of the type \( \frac{\partial T}{\partial q_k} \), where \( T \) and \( q_k \) are the kinetic energy and a generalized coordinate, respectively, if occurring in the equation of motion of a system is called a:
For inverse square law forces, the mathematical statement of the virial theorem is (where \( \langle T \rangle \) and \( \langle V \rangle \) are the averages of kinetic and potential energies):
The types of constraints on the mechanical system consisting of a cylinder rolling (and possibly sliding) down an inclined plane of angle \( \alpha \) are:
Displacement \( x^i \) is a contravariant vector. The work done by a force is an invariant scalar. Therefore, force and hence momentum are:
A photon recoils back after striking an electron at rest. The change in wavelength of the photon is:
A solenoid has length \( l \), number of turns \( N \), and area of cross-section \( A \). Its self-inductance \( L \) is:
The loss of energy due to hysteresis when 5 kg of iron is subjected for 1 hour to cyclic magnetic changes of frequency 25 cycles/sec, if the hysteresis loop represents a loss of \( 2.5 \times 10^3 \) erg cm\(^3\) cycle\(^{-1}\) and density of iron is 7.8 gm cm\(^{-3}\), is:
The de-Broglie wavelength \( \lambda \) associated with an electron of energy \( V \) electron volt is:
A coil of inductance 2 mH and resistance 15Ω is connected in parallel with a capacitor of 0.01 μF. The peak oscillator current at resonance is:
Two inductors \( L_1 \) and \( L_2 \) are connected such that their fluxes are in opposite directions. The total inductance \( L \) will be:
Polarization \( \vec{P} \) and electric susceptibility \( \chi \) are related as:
The Clausius-Mossotti relation holds best for:
Using Langevin's theory, the susceptibility \( \chi \) of a paramagnetic substance is given by:
The polarizability of atoms in the air molecule is \( 9.7 \times 10^{-41} \, \text{cm}^2/\text{V} \). The radius of the atom of an air molecule is:
Above Curie temperature, the ferromagnetic material behaves as:
Circularly polarized light is produced if the amplitudes of the ordinary and extraordinary rays are equal and there is a phase difference of:
When a single slit is replaced by a double-slit arrangement, the intensity of the central maximum is increased by:
In the diffraction pattern due to a single slit, the width of the central maximum will be:
In a plane transmission grating, the angle of diffraction for the second-order principal maxima for wavelength \( 5000 \) Å is \( 30^\circ \). The number of lines per cm of the grating surface is:
If \( N \) is the total number of rulings on the grating, \( n \) is the order of the spectrum, and \( \lambda \) is the wavelength of light, then the resolving power of the grating is:
The minimum number of lines in a plane diffraction grating required to just resolve the sodium doublet (5890 Å and 5896 Å) in first order is:
A movable mirror of Michelson’s interferometer is moved through a distance of 0.06 mm. If 200 fringes cross the field of view, the wavelength of light is:
In interference with coherent sources, the fringe width varies as:
In Newton’s rings experiment with two different media between the glass surfaces, the nth rings have diameters as 10:7. The ratio of the refraction indices of two media are:
Broad sources are required in: