List of top Physics Questions asked in Banaras Hindu University Postgraduate Entrance Test

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:
The radius of the first zone in a zone plate of focal length 40 cm for light of wavelength 4000 Å 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:
If a black body radiation enclosure expands, so that its volume becomes 64 times, the temperature of the enclosure becomes:
Which of the following statements is correct?
Which of the following is not correct for the first order phase transition?
In the inversion curve for a gas, in the region of cooling:
At constant temperature, the internal energy of a Van der Waals gas:
Specific heat of saturated steam is:
States of thermodynamic equilibrium can be described in terms of:
The ratio of isobaric volume expansivity and isothermal compressibility is given as:
During a quasi-static process:
Mathematical formulation of the first law contains the idea of:
One liter atmosphere equals:
At \( 4^\circ C \) for water, \( C_P = C_V \) because: