Physics M.C.Q (1 Marks)

Imagine an atom made up of a proton and a hypothetical particle of double the mass of the electron but having the same charge as the electron. Apply the Boh’r atom model and consider all possible transitions of this hypothetical particle to the first excited level. The longest wavelength photon that will be emitted has wavelength l (given in terms of the Rydberg constant R for the hydrogen atom) equal to

Thermal neutrons can cause fission in

The mass defect in a particular nuclear reaction is 0.3 grams. The amount of energy liberated in kilowatt hours is (Velocity of light = 3)

The diagram shows-the energy levels for an electron in a certain atom. Which transition shown represents the emission of a photon with the most energy

The diagram shows the path of four a-particles of the same energy being scattered by the nucleus of an atom simultaneously. Which of these are/is not physically possible

The energy equivalent of 1 kilogram of matter is about

In the lowest energy level of hydrogen atom, the electron has the angular momentum

The following diagram indicates the energy levels of a certain atom when the system moves from 2E level to E, a photon of wavelength λ  is emitted. The wavelength of photon produced during its transition from   level to E is

The angular momentum of electron in n^th orbit is given by

The Rutherford a-particle experiment shows that most of the a-particles pass through almost unscattered while some are scattered through large angles. What information does it give about the structure of the atom

Excitation energy of a hydrogen like ion in its first excitation state is 40.8 eV. Energy needed to remove the electron from the ion in ground state is

After 280 days, the activity of a radioactive sample is 6000 dps. The activity reduces to 3000 dps after another 140 days. The initial activity of the sample in dps is

The half-life of a radioactive substance is 40 years. How long will it take to reduce to one fourth of its original amount and what is the value of decay constant

In the following reaction   is

In a fission reaction , the binding energy per nucleon of X and Y is 8.5 MeV whereas of  is 7.6 MeV. The total energy liberated will be about

Atomic weight of boron is 10.81 and it has two isotopes  and  . Then ratio of  in nature would be

The ratio of the largest to shortest wavelengths in Lyman series of hydrogen spectra is

The energy levels of the hydrogen spectrum is shown in figure. There are some transitions A, B, C, D and E. Transition A, B and C respectively represent

Radon (Ra) decays into Polonium ( by emitting an α - particle with half-life of 4 days. A sample contains 6.4  atoms of Rn. After 12 days, the number of atoms of  left in the sample will be

The half life period of radium is 1600 years. The fraction of a sample of radium that would remain after 6400 years is

Solar energy is mainly caused due to

Light energy emitted by stars is due to

Work of moderator is

The example of nuclear fusion is

Fission of nuclei is possible because the binding energy per nucleon in them

If the mass number of an atom is A = 40 and its electron configuration is  , the number of neutrons and protons in its nucleus will be

If in a nuclear fission, piece of uranium of mass 0.5 g is lost, the energy obtained in kWh is

(a) 1.25

(b) 2.25

(c) 3.25

(d) 0.25

The curve of binding energy per nucleon as a function of atomic mass number has a sharp peak for helium nucleus. This implies that helium

A nucleus is bombarded with a high speed neutron so that resulting nucleus is a radioactive one. This phenomenon is called

What is used as a moderator in a nuclear reactor

A nucleus of   originally at rest emits a particle with speed v. What will be the recoil speed of the daughter nucleus

Nuclear fusion is common to the pair

The principle of controlled chain reaction is used in

Heavy water is

Mark the correct statement

The binding energy of nucleus is a measure of its

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

Taking Rydberg’s constant  first and second wavelength of Balmer series in hydrogen spectrum is

The kinetic energy of an electron revolving around a nucleus will be

As the electron in Bohr orbit of Hydrogen atom passes from state n = 2 to n = 1, the kinetic energy K and potential energy U change as

The ground state energy of hydrogen atom is – 13.6 eV. What is the potential energy of the electron in this state

The energy of electron in the nth orbit of hydrogen atom is expressed as . The shortest and longest wavelength of Lyman series will be

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

(a)

(b)

(c)

(d)

In the spectrum of hydrogen atom, the ratio of the longest wavelength in Lyman series to the longest wavelength in the Balmer series is

The ratio of areas within the electron orbits for the first excited state to the ground state for hydrogen atom is

The colour of the second line of Balmer series is

The Bohr model of atoms            

The shortest wavelength in the Lyman series of hydrogen spectrum is 912 Å corresponding to a photon energy of 13.6 eV. The shortest wavelength in the Balmer series is about

Which of the following is quantised according to Bohr’s theory of hydrogen atom

Radius of first Bohr orbit is r. What is the radius of 2^nd Bohr orbit?

(a) 8r

(b) 2r

(c) 4r

(d) 2