Chemistry Question Bank

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

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)

The ionization enthalpy of hydrogen atom is 1.312 × 10⁶ J mol⁻¹. The energy required to excite the electron from n = 1 to n = 2 is

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

Which of the following electronic transitions in a hydrogen atom will require the largest amount of energy?

Early Indian and Greek philosophers were of the view that 'A' are the fundamental building blocks of matter. Here, 'A' refers to

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

Bohr's theory is NOT applicable to:

According to Bohr's theory, the angular momentum of an electron in 5th orbit is

When electrons of a hydrogen atom return to the L shell (n=2) from higher energy shells, the series of lines formed is called

Which series in the hydrogen spectrum lies in the ultraviolet region?

In the hydrogen spectrum, the Balmer series lies in which region?

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 …)

Which of the following statements does NOT form a part of Bohr's model of hydrogen atom?

The value of a₀ (Bohr radius) in the expression for the radius of nth orbit of hydrogen atom (rₙ = n²a₀) is

Electronic energy is negative because

According to Bohr model, angular momentum of an electron in the 3rd orbit is

The Bohr orbit radius for hydrogen atom (n = 1) is 0.529 Å. The radius for the first excited state (n = 2) orbit is

Energy of electron of hydrogen atom in the second Bohr orbit is

A 4000 Å photon is used to break the I₂ molecule. The bond dissociation energy of I₂ is 246.5 kJ/mol. The % of photon energy converted to kinetic energy of iodine atoms is

A photon of 300 nm is absorbed by a gas and then re-emits two photons. One re-emitted photon has wavelength 496 nm. The wavelength of the second re-emitted photon is

A 20 W light source emits monochromatic light of wavelength 600 nm. The number of photons ejected per second expressed in terms of Avogadro's constant N_Av is approximately