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S1
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P1
P1R
P2
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PHYSICS Exam 27.01.2013
S1. Define with your own words the first principle of dynamics. Give an example of a body with the mass between 10 kg and 100 ks.
Compare from this potion of view the linear with the circular motion of selected body.
S2. Give an example of a mechanic forced oscillatory motion.
S3. A wind blow characterized by a velocity of 100 m/s and mass of 650 kg act on a building during 10 s. Use the definition of force
related to the linear momentum to calculate the wind force and pressure on building, if the exposed surface is 50 m2 (the use of
acceleration is not considered).
S4. Identify the expression: A 

F0

2 2
m  
2
0
 4 
2
[cm], and give the name of the involved physical quantities. Name
2
all physical quantities and give the measurement unit.
S5. Discuss the Coriolis force of inertia (physical formula; name the physical quantities involved; picture).
Conf Dr. Radu Fechete
(0.5) from start (1p)-S1 (0.5p)-S2 (1p)-S3 (1p)-S4 (1p)-S5
S6. Calculate the sound level of a sound at 10 cm away from a PC-fan if the effective sound pressure is 0.04421/2 N/m 2 and the
acoustic impedance is 442 Ns/m3 (I0 = 10-12 W/m2).
S7. Write the Maxwell equations (differential form) and name al physical quantities.
S8. Write the general form of space dependent Schrödinger equation (along z direction) for a particle into a region of space where the
potential energy, U is 4 times larger than the total energy, E. Name the involved physical quantities. Enumerate the properties of
the wave function.
S9. Calculate the wavelength (approximate the order of magnitude) associated to an electron accelerated at U = 54 V if you know: me
 9.11 × 10-31 kg; e = 1.6× 10-19 C; h = 6.62 × 10-34 Js. (Key words: de Broglie, kinetical energy expressed function of linear
momentum, kinetical energy expressed in eV).
S10. The Pauli principle states that: Into an atom (molecule) there are no two electrons (in general fermions) characterized by
identical quantum numbers. Name these four quantum numbers and calculate the maximum number of orbitals for a hidrogenoid
atom with two electrons characterized by i) n1 = 2 and ii) n2 = 5 and l is maximum.
Conf Dr. Radu Fechete
(0.5) from start (0.5p)-S6 (1p)-S7 (1p)-S8 (1p)-S9 (1p)-S10