Atoms And Nuclei - Modern Physics - Physics Previous Year Questions

An electron of an atom transits from \(n_1\) to \(n_2\). In which of the following maximum frequency of photon will be emitted?

Two radioactive materials X\(_1\) and X\(_2\) have decay constant 5\(\lambda\) and \(\lambda\), respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of X\(_1\) to X\(_2\) will be \(1/e\) after a time

Two protons are kept at a separation of 40 \(\mathop A\limits^o\). F\(_n\) is the nuclear force and F\(_e\) is the electrostatic force between them. Then,

The Lyman series of a hydrogen atom belongs in which category

Ba-122 has half-life of 2 min. Experiment has to be done using Ba-122 and it takes 10 min to set up the experiment. It initially 80 g at Ba-122 was taken, how much Ba was left when experiment was started?

If an electron in hydrogen atom jumps from an orbit of level \(n=3\) to an orbit at level \(n=2\), emitted radiation has a frequency of

(R = Rydberg's constant and c = velocity of light)

When the speed of light becomes \(\frac{2}{3}\) of its present value, then the energy released in a given atomic explosion would

The wavelength of the second line of Balmer series is 486.4 nm. What is the wavelength of the first line of Lyman series?

During \(\alpha\)-decay, atomic mass of parent nuclei is

Which of the following series spectrum of hydrogen atom lies in ultraviolet region?

A particle at rest decays in to two particles of mass \(m_1\) and \(m_2\) and move with velocities \(v_1\) and \(v_2\). The ratio of their de Broglie wave length \(\frac{\lambda_1}{\lambda_2}\) is:

In the head-on collision of two alpha particles \(\alpha_1\) and \(\alpha_2\) with the gold nucleus, the closest approaches are 31.4 fermi and 94.2 fermi respectively. Then the ratio of the energy possessed by the alpha particles \(\alpha_2 / \alpha_1\) is:

The mass number of two nuclei \(\mathrm{P}\) and \(\mathrm{Q}\) are 27 and 125 respectively. The ratio of their radii \(R_P: R_Q\) is given by:

Which of the following statement is true when a gamma decay occurs from the nucleus of an atom?

In a nuclear reaction 2 deuteron nuclei combine to form a helium nucleus. The energy released in \(\mathrm{MeV}\) will be: (Given mass of deuteron \(=2.01355 \mathrm{~amu}\). and mass of helium nucleus \(=4.0028 \mathrm{~amu}\).

The ground state energy of hydrogen atom is \(-13.6 \mathrm{~eV}\). If the electron jumps from the \(3^{\text {rd }}\) excited state to the ground state then the energy of the radiation emitted will be:

A nucleus with mass number 190 initially at rest emits an alpha particle. If the \(\mathrm{Q}\) value of the reaction is \(4.5 \mathrm{~MeV}\), the kinetic energy of the alpha particle is

In a hydrogen atom, if electron is replaced by a particle which is 40 times heavier but has the same charge, then, the ratio of the radius of the first excited state of a normal hydrogen atom to the ground state of the above atom is

The radius of a nucleus as measured by electron scattering is \(4.8 \mathrm{~fm}\). The mass number of nucleus is most likely to be

The shortest wavelengths of Paschen, Lymen and Balmer series are in the ratio