Task 4.10
The kinetic energy of a neutron is equal to its rest energy. Determine the de Broglie wavelength
Neutron.

Problem 4.20
The natural width of the spectral line? = 0.55 μm corresponding to the transition of the atom to the ground
State is equal to 0.01 pm. Determine the mean lifetime of the excited state of the atom.
Task 4.30
The particle is in an infinitely deep one-dimensional potential well of width l, Calculate
The ratio of the probabilities of finding a particle in the range from 0 to l / 4 for the first and second
Energy levels.

Task 4.40
The wavelength of the Ka-line of the characteristic X-ray radiation is 0.194 nm. From what
Material made anti-cathode?
Task 4.50
Find the half-life of the radioactive preparation, if for a day its activity decreases to three
Times.
Task 4.60
Calculate the energy of the nuclear reaction 42He + 147N-> 178O + p.
Task 4.70
What is the sum of the mean occupation numbers of free electrons in a metal of levels with energy
Greater and lower Fermi energy by the same amount.
Task 4.80
Determine the impurity electrical conductivity of silicon containing boron with a concentration of 2 • 1022 m-3 and
Antimony with a concentration of 3 • 1021 m-3. The mobility of electrons and holes for silicon is, respectively,
0.13 and 0.05 m2 / (B · s).