19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
Mass of neutron is about ________ times the mass of the electron.
Which of the following statements does NOT form a part of Bohr's model of hydrogen atom?
For a Bohr atom, angular momentum of the electron is (n = 1, 2, 3 …)
The ratio of the energy difference between the 1st and 2nd Bohr orbits to that between the 2nd and 3rd Bohr orbits is
In the hydrogen spectrum, the Balmer series lies in which region?
Which series in the hydrogen spectrum lies in the ultraviolet region?
When electrons of a hydrogen atom return to the L shell (n=2) from higher energy shells, the series of lines formed is called
According to Bohr's theory, the angular momentum of an electron in 5th orbit is
Bohr's theory is NOT applicable to:
The velocity of an electron in the second shell of hydrogen atom is
The most probable radius (in pm) for finding the electron in He⁺ is
The minimum frequency ν₀, below which the photoelectric effect is not observed, is called
If the total energy of an electron in the 1st shell of H atom = 0.0 eV (reference shifted), then its potential energy in the 1st excited state would be
In any subshell, the maximum number of electrons having the same value of spin quantum number is
Positive rays (canal rays) are:
A stream of electrons is passed between two charged plates at potential difference V (esu). If e and m are charge and mass of electron, the value of h/λ (λ = de Broglie wavelength) is
Ultraviolet light of 6.2 eV falls on an aluminium surface (work function = 4.2 eV). The kinetic energy (in joule) of the fastest electron emitted is approximately:
The threshold wavelength for the photoelectric effect on sodium is 5000 Å. Its work function is:
If the threshold frequency of a metal for the photoelectric effect is ν₀, which of the following will NOT happen?
The energy of an electron in the 3rd orbit of hydrogen atom is
The ionization energy of H atom is 13.6 eV. The ionization energy of Li²⁺ ion will be
The frequency of light emitted for the transition n = 4 to n = 2 of He⁺ is equal to the transition in H atom corresponding to which of the following?
The emission spectra of He⁺ ions show 6 different photons. What will be the minimum wavelength during the transition? (R_H = Rydberg constant)
A mixture of ethane and ethene occupies 40 litre at 1.00 atm and at 400 K. The mixture reacts completely with 130 g of to produce and . Assuming ideal gas behavior, calculate the mole fraction of and in the mixture.
What volume of 0.010 M is required to react completely with 30 g of an aqueous acetic acid solution in which mole fraction of acetic acid is 0.15?