p-type and n-type semiconductors can be distinguished by

In Young’s double silt experiment if the slit widths are in the ratio 1 : 9, the ratio of the intensity at minima to that at maxima will be

A cube have side 10 m when at rest relative to an observer. The cube now moves with a speed 0.8 c (c = speed of light in vacuum) relative to the same observer and parallel to one of its sides. Volume of the cube is found to change by

In Hydrogen atom, an electron makes a de-excitation transition from n =5 such that change of radius of the orbit is 21 times the radius of that orbit in which the binding energy of electron is –13.6 eV. Due to the de-excitation transition angular momentum changes by

Difference in the frequencies of series limits of Lyman series and Brackett series is equal to the frequency of

When an electron in the target atom of X-ray tube is transferred from the L-shell to the Kshell, the emitted X-rays have a wavelength of 0.788 Å. This atomic number of atom is

The phase velocity of the deBroglie wave corresponding to a particle moving with some velocity is

When stopping potential is applied in an experiment on photoelectric effect, no photocurrent is observed. This means that