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An X-ray line of wavelength 0.53832A0 is found to be emitted from an X− ray tube with (Z= 30) target in addition to the characteristic Kα line of Zinc of wavelength 1.43603A0 . If the unkown line is due to an impurity in the target, obtain the atomic number of the impurity.
The Hydrogen atom in its ground state is excited by means of a monochromatic radiation of wavelength 970.6A0 . How many different wavelengths (transitions) are possible in the resulting emission spectrum ? [NB: you have to represents them on a diagram]. Find the longest wavelength amongst these.
In the Helium-Neon laser, lasing occurs between two excited states of the neon atom. However, in many lasers lasing occurs between the ground state and an excited state. Consider such a laser that emits at wavelength λ = 550 nm. If a population inversion is not generated, (i) what is the ratio of the population of atoms in state Ex to the population in the ground state E0 with atoms at room temperature? For the condition in (i), at (ii) what temperature would the ratio Nx/N0 be 1/2?.
How much energy (in Joules) will be produced on complete fission of 1 kg of Uranium (235U), considering that only 0.1% of mass is converted into energy.
3. (i) In the presence of an external uniform magnetic field, the normal Zeeman effect is observed
and the original transition generates into three transitions of frequencies:
ν = ν0 −
eB
4πm
; ν = ν0; ν = ν0 +
eB
4πm
where m is the mass of the electron. Using a diagram, indicate what are allowed normal
Zeeman transitions between d(l = 2) state and p(l = 1) state. [6 marks]
(ii) Find the minimum magnetic field needed for the Zeeman effect to be observed in a
spectral line of 400 nm wavelength when a spectrometer whose resolution is 0.010 nm is
used.
(a) Compute the energy released from a pair production reaction. [2 marks]
(b) Using the line of stability curve, briefly explain why Helium 6
2He is unstable and would
eventually decay into 6
3Li. Indicate the corresponding decay reaction equation. [4 marks]
(c) The Figure bellow represents a typical X-ray spectrum from a tungsten target. Explain the
behaviour of the observed spectrum as far the mechanism of X-ray production is concerned.
[4 marks] .
Determine approximately the ratio of the probability of spontaneous emission
to the probability of stimulated emission at room temperature in (a) X-ray
region of the EM spectrum (b) the visible region (c) the microwave region.
On 20 July 1969, the astronauts of Apollo 11 placed a reflector on the surface of the moon that with the telescope and electronic equipment on earth allows measurements of the time of flight of laser pulses from earth to the moon and back. Scientists are able to measure the time of flight of laser pulse from earth to the moon and back with an accuracy of one nanosecond. What is the accuracy of the distance to the moon distance?
What are the quantum numbers for the electrons in the lithium atom (Z =
3) when the atom is in its ground state?
and do the Same question as 5 for Sodium (Z = 11).
An electron beam in an X-ray tube is accelerated through 40kV and is incident on a tungsten target. What is the shortest wavelength emitted by the tube?
