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The decay constant of radioactive substance is 4.33 x 10-4 per year. Calculate its half life period.
Concept: Law of Radioactive Decay
With the help of a neat labelled diagram, describe the Geiger- Marsden experiment
Concept: Alpha-particle Scattering and Rutherford’s Nuclear Model of Atom
An electron is orbiting in 5th Bohr orbit. Calculate ionisation energy for this atom, if the ground state energy is -13.6 eV.
Concept: Bohr’s Model for Hydrogen Atom
Obtain an expression for the radius of Bohr orbit for H-atom.
Concept: Bohr’s Model for Hydrogen Atom
State Bohr’s third postulate for hydrogen (H2) atom. Derive Bohr’s formula for the wave number. Obtain expressions for longest and shortest wavelength of spectral lines in ultraviolet region for hydrogen atom
Concept: Bohr’s Model for Hydrogen Atom
Light of a certain wavelength has a wave number `barv` in vacuum. Its wave number in a medium of refractive index n is _______.
Concept: Wavelength of an Electron
Calculate the de Broglie wavelength of an electron moving with - of the speed of light in vacuum (Negelct relativistic effect)
(Planck's constant: h = 6.63 x 10-34 Js, Mass of electron : m = 9.11 x 10-28 g)
Concept: de-Broglie Relation
Derive an expression for the total energy of electron in ‘n' th Bohr orbit. Hence show that energy of the electron is inversely proportional to the square of principal quantum number. Also define binding energy.
Concept: Mass-energy and Nuclear Binding Energy >> Nuclear Binding Energy
The nuclei having same number of protons but different number of neutrons are called ___ .
(a) isobars
(b) a-particles
(c) isotopes
(d) y-particles
Concept: Hydrogen Spectrum
Describe the construction of photoelectric cell.
Concept: Wave Nature of Matter
Draw a neat labelled diagram for Davisson and Germer experiment, for diffraction of electron wave.
Concept: Davisson and Germer Experiment
Calculate the radius of second Bohr orbit in hydrogen atom from the given data.
Mass of electron = 9.1 x 10-31kg
Charge on the electron = 1.6 x 10-19 C
Planck’s constant = 6.63 x 10-34 J-s.
Permittivity of free space = 8.85 x 10-12 C2/Nm2
Concept: Bohr’s Model for Hydrogen Atom
In a photon-electron collision ______.
(A) only total energy is conserved.
(B) only total momentum is conserved.
(C) both total energy and total momentum are conserved.
(D) both total momentum and total energy are not conserved
Concept: Forms of Energy > Nuclear Energy >> Nuclear Fusion – Energy Generation in Stars
Find the frequency of revolution of an electron in Bohr’s 2nd orbit; if the radius and speed of electron in that orbit is 2.14 × 10-10 m and 1.09 × 106 m/s respectively. [π= 3.142]
Concept: Bohr’s Model for Hydrogen Atom
Draw a neat, labelled energy level diagram for H atom showing the transitions. Explain the series of spectral lines for H atom, whose fixed inner orbit numbers are 3 and 4 respectively.
Concept: Bohr’s Model for Hydrogen Atom
Thorium 90Th232 is disintegrated into lead 82Pb200. Find the number of α and β particles emitted in disintegration.
Concept: Alpha-particle Scattering and Rutherford’s Nuclear Model of Atom
Find the ratio of longest wavelength in Paschen series to shortest wavelength in Balmer series.
Concept: Wavelength of an Electron
The ratio of kinetic energy of an electron in Bohr’s orbit to its total energy in the same orbit is
(A) – 1
(B) 2
(C) 1/2
(D) – 0.5
Concept: Bohr’s Model for Hydrogen Atom
In hydrogen atom Balmer series is obtained when the electron jumps from ............ .
(a) higher orbit to first orbit
(b) first orbit to a higher orbit
(c) higher orbit to the second orbit
(d) second orbit to a higher orbit
Concept: Wavelength of an Electron
What is de Broglie wavelength of an electron accelerated through 25000 volt?
Concept: Wavelength of an Electron
