Address: Budapest, 1117, Pázmány Péter sétány 1/a.
Mailing address: H-1518 Budapest Pf.32
Phone of secretary: +36-1-372-2845
E-mail: titkar kukac metal.elte.hu
Laboratory of Classical Physics
Head of the Laboratory:
András Böhönyey assistant professor,
Department of Materials Physics,
Pázmány Péter sétány 1/A. room N. 5.76.
E-mail: boh kukac ludens.elte.hu
Images of the laboratory: image 1, image 2
1. Gravitational acceleration (images)
The gravitational acceleration (g) is determined by measuring the period-time of a pendulum. The reversible
pendulum, used in this measurement, is a physical pendulum, which can be oscillated around two axes. The
measurement of g with high accuracy (< 0,1%) can be accomplished by a measurement-series successively
changing the centre of gravity of this pendulum by a movable bob.
2. Elastic constants (images)
The Young's modulus of a bar supported at two ends and loaded at the centre is determined measuring its
deflection by a dial-gauge. Additionally, the torsion modulus of a metallic wire is determined measuring the
period time of a torsion pendulum.
3. Harmonic vibration of rods (images)
The harmonic forced oscillations of a bar clamped at one end are investigated measuring the eigen-frequencies
and the resonance curve of the self oscillation. The eddy current excitation and the piezoelectric detection
permit the high accuracy measurement of the dynamical Young's modulus.
4. Peltier coolers (images)
The thermal properties of a semi-conducting Peltier cooling element are studied. One can measure the current-
equilibrium temperature relationship, the Peltier coefficient characterising the amount of subtracted heat in
cooling, and the Seebeck-coefficient characterising the potential differences appearing between the ends of the
cooling element. Such simple cooling elements are used in refrigerators and for cooling of computer processors.
5. Specific heat (images)
Specific heat of metallic samples is measured by electric calorimeter. The time-temperature curves are measured
by computer. The measurements are accomplished by two different methods. In the first method the heated up
sample is dropped into the calorimeter and the development of the mutual temperature is measured. In the second
method the sample and the calorimeter are heated together and we measure the change of temperature, and
compare it with the temperature change of the empty calorimeter.
6. Phase transition of metals (images)
The melting point of metals is measured and the latent heat is calculated in this practice. The metallic samples
are heated in electric furnace. The linear heating and cooling are controlled by thermocontroller. The changes in
temperature of the furnace and the sample are measured by computer. The evaluation of the measured data is
supported by computer as well.
7. Magnetic susceptibility (images)
Paramagnetic and diamagnetic susceptibility of rod-like samples are measured by the Gouy method. This methods
needs the high accuracy measurement of the magnetic field. The magnetic field is measured by Hall detector, which
is calibrated by a flux-meter. According to the method, a force acts to the sample placed into an inhomogeneous
magnetic field, and this force is proportional to the susceptibility. Thus, measuring the magnetic field and the force,
the susceptibility can be calculated. The force is measured by balance with high accuracy.
8. Optical microscope, Newton rings
Refractive index of liquids (images)
The basic principles of the optical microscope are studied in this practice. The main parameters of the
microscope are measured: magnification, focal length and numeric aperture. Using the measured parameters the
resolution can be calculated. The radius of curvature of a lens is determined by the measurement of the diameter
of Newton rings. Refractive indices of solution serious is measured by Abbe refractometer as a function of the
solution concentration and this enables us to determine the concentration of an unknown solution.
9. Wave length of light and dispersion of the refractive index (images)
The dispersion properties of grating and prism is investigated using optical goniometer. The light of a spectral lamp
is resolved by a grating and the wavelengths of the spectral lines are determined. Using the wavelength data the
refractive index-wavelength dependence of the prism's glass material is investigated.
10. Fraunhofer and Fresnel diffraction (images)
The diffraction of a laser beam on a slit, double slit, thin string and on a half field is examined using a He-Ne laser.
The Fraunhofer and Fresnel diffraction spectra are measured using a semiconductor detector moved by a step motor.
The detector signal is proportional to the diffracted light intensity. This is measured and evaluated by a computer
program. In the evaluation the size and the arrangement of the diffraction objects can be deduced. The principle is
analogous to the method used in X-ray and electron diffraction to determine the geometrical parameters of a crystal.