Atom And Nuclei - Online Test - Class 12 MCQ

Half-life period of a radioactive element X is same as the mean-life time of another radioactive element Y. If initially both have same number of atoms, then

Activity of a radioactive material decreases to one third in 10 years. After 10 more years, final activity will be

Binding energy of deuterium is 2.23 MeV. Mass defect in amu is

When an electron jumps from the orbit n = 2 to n = 4, then wavelength of the radiations absorbed will be where R is Rydberg s constant

Half life of a radioactive substance is 10 second. Then undecayed nuclei of the substance will reduce to 6.25% of their value at t = 0 in a time of

Amount of original radioactive atom left after 5 half lives will be

the ratio of magnetic dipole moment to the angular momentum of the electron in the first orbit of hydrogen atom is

Hydrogen atom is excited from ground state to another state with principal quantum number equal to 4. Then the number of spectral lines in the emission will be

The magnetic moment (µ) of a revolving electron around the nucleus varies with principal quantum number n as

Which one of the following is not a possible energy for a photon to be emitted by hydrogen atom according to bohr’s atomic model

The radius of hydrogen atom in its ground state is 5.3 x 10^-11 m. after collision with an electron it is found to have a radius of 21.2 x 10^-11m. what is the principle quantum number n of the final state of the atom

First and second wavelength of Balmer series in hydrogen spectrum is (R_H = 1.097 X 10⁷ m)

The kinetic energy of electron in the first Bohr orbit of the hydrogen atom is

The ratio of minimum wavelengths of Lyman and Balmer series will be

When an α- particle of mass m moving with velocity bombards on a heavy nucleus of charge Ze, its distance of closest approach from the nucleus depends on m as

The wavenumber of last line of balmer series in hydrogen spectrum will be

Two nuclei have their mass number in the ratio of 1:3. The ratio of their nuclear densities would be

The correct order of ionizing capacity of α, β and γ rays is

A radioactive nucleus(mass number A and atomic number Z) emits 3 α particles and 2 positrons. The ratio of number of neutrons to that of proton in the final nucleus will be

A nucleus _nX^m emits one α and one β particle. The resulting nucleus is

Binding energy per nucleon plotted against the mass number for stable nuclei is shown in the figure. Which curve is correct

. Radioactive element decay to form a stable nuclei then the rate of decay of reactant will vary with time as shown  in the figure

The energy spectrum of β particles as a function of β energy emiited from a radioactive source is

Which of the relation is correct between time period and number of orbits while an electron is revolving in an orbit

If scattering particles are 56 for 90⁰ angle,then at an angle 60⁰ will be

In the spectrum of hydrogen, the ratio of the longest wavelength in the Lyman series to the longest wavelength in balmer series

The wave number of a photon in bracket series of hydrogen atom is 9R/400. The electron has transited from the orbit having quantum number