19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
Assertion (A): For Balmer series of hydrogen spectrum, the value of n₁ = 2 and n₂ = 3, 4, 5 ... Reason (R): The value of n for a line in Balmer series having the highest wavelength is n₁=4 and n₂=6.
The number of unpaired d-electrons retained in Fe²⁺ ion (At. no. of Fe = 26) is
The electrical discharge through gases could be observed only at
The correct set of four quantum numbers for the valence electron of rubidium (Z = 37) is
Which of the following electronic transitions in a hydrogen atom will require the largest amount of energy?
The most probable radius (in pm) for finding the electron in He⁺ is
The velocity of an electron in the second shell of hydrogen atom is
According to Bohr's theory, the angular momentum of an electron in 5th orbit is
The ratio of the energy difference between the 1st and 2nd Bohr orbits to that between the 2nd and 3rd Bohr orbits is
For a Bohr atom, angular momentum of the electron is (n = 1, 2, 3 …)
If the threshold frequency of a metal for the photoelectric effect is ν₀, which of the following will NOT happen?
Energy of electron of hydrogen atom in the second Bohr orbit 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:
[NEET 2014] Calculate the energy in joule corresponding to light of wavelength 45 nm. (h = 6.63 × 10⁻³⁴ Js, c = 3 × 10⁸ ms⁻¹)
[NEET 2022] If the radius of the second Bohr orbit of He⁺ ion is 105.8 pm, what is the radius of the third Bohr orbit of Li²⁺ ion?
As an electron moves away from the nucleus, its potential energy
The correct ground state electronic configuration of chromium atom (Z = 24) is
Aufbau principle does NOT give the correct arrangement of filling of atomic orbitals in
The correct order of increasing energy of orbitals in hydrogen atom is
[CBSE AIPMT 2015] The number of d-electrons in Fe²⁺ (Z = 26) is NOT equal to the number of electrons in which one of the following?
[NEET 2019] Orbital having 3 angular nodes and 3 total nodes is
[NEET 2019] 4d, 5p, 5f and 6p orbitals are arranged in order of decreasing energy. The correct option is
The e/m ratio for anode rays (positive rays) in comparison to cathode rays is:
The energy required to break one mole of Cl–Cl bonds in Cl₂ is 242 kJ mol⁻¹. The largest wavelength of light capable of breaking a single Cl–Cl bond is
The number of photons emitted in 10 hours by a 60 W sodium lamp (λ = 6000 Å) is approximately