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The angular momentum of an electron in the 3rd Bohr orbit of a Hydrogen atom is 3.165 × 10-34 kg m2/s. Calculate Plank’s constant h.
Concept: Bohr’s Atomic Model
The half-life of a certain radioactive nucleus is 3.2 days. Calculate (i) decay constant (ii) average life of radioactive nucleus.
Concept: Radioactive Decays
Derive an expression for the radius of the nth Bohr orbit for the hydrogen atom.
Concept: Bohr’s Atomic Model
Show that for radioactive decay N(t) = `"N"_"O" "e"^{-λ"t"}`, where symbols have their usual meaning.
Concept: Radioactive Decays
Obtain an expression for the half-lifetime of radioactive material. Hence state the relation between an average life and half life time of radioactive material.
Concept: Radioactive Decays
A radioactive substance decays to (1/10)th of its original value in 56 days. Calculate its decay constant.
Concept: Radioactive Decays
Calculate the shortest wavelength in the Paschen series if the longest wavelength in the Balmar series is 6563 Ao.
Concept: Bohr’s Atomic Model
State the postulates of Bohr’s atomic model. Hence show the energy of electrons varies inversely to the square of the principal quantum number.
Concept: Bohr’s Atomic Model
What is the mathematical formula for the third postulate of Bohr's atomic model?
Concept: Bohr’s Atomic Model
Determine the shortest wavelengths of Balmer and Pasch en series. Given the limit for the Lyman series is 912 Å.
Concept: Atomic Spectra
The disintegration rate of a radio-active sample is 1010 per hour at 20 hours from the start. It reduces to 5 × 109 per hour after 30 hours. Calculate the decay constant.
Concept: Radioactive Decays
State unit and dimensions of Magnetic susceptibility.
Concept: Magnetisation and Magnetic Intensity
State the significance of binding energy per nucleon.
Concept: Mass-energy and Nuclear Binding Energy >> Nuclear Binding Energy
Concept: Bohr’s Atomic Model
Concept: Bohr’s Atomic Model
What is binding energy of a hydrogen atom?
Concept: Mass Defect and Binding Energy
Calculate the wavelength of the first two lines in the Balmer series of hydrogen atoms.
Concept: Atomic Spectra
The co-efficient of mutual induction between primary and secondary coil is 2H. Calculate induced e.m.f. if current of 4A is cut off in 2.5 x 10-4 seconds
Concept: Inductance >> Mutual Inductance
Electric field intensity in free space at a distance ‘r’ outside the charged conducting sphere of radius ‘R’ in terms of surface charge density ‘ a ’ is............................
(a)`sigma / in_0[R/r]^2`
(b)`in_0/sigma[R/r]^2`
(c)`R/r[sigma/in_0]^2`
(d)`R/sigma[r/in_0]^2`
Concept: Electromagnetic Induction
A solenoid 3.142m long and 5.0 cm in diameter has two layers of windings of 500 turns each and carries a current of 5A. Calculate the magnetic induction at its centre along the axis.
Concept: Inductance and Capacitance
