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Laboratory work #37
OHM’S LAW VERIFICATION AND SPECIFIC RESISTANCE
OF A CONDUCTOR DETERMINATION

Aim of work: to investigate the dependence of the current
strength in the conductor on the potential difference at its ends and to
determine the specific resistance of the conductor on the basis of

experimental data.
Laboratory equipment: laboratory stand №37. Ammeter,
voltmeter, current source, rheostat.

1. Theoretical knowledge.
According to the experimental Ohm law: the current I in a

homogeneous metal conductor is proportional to the potential
difference U at the ends of this conductor and is inversely
proportional to the value of R, which is called the electrical
resistivity of the conductor.

U
I  (37.1)
R

This is Ohm's law for the area of the circle, where there are no
extraneous forces, that is, the forces of non-electric nature. In this case,

the area of the circle and the conductor of the given section of the
circle are called homogeneous. According to Ohm's law, the unit of
resistance is set to 1 Ohm.

1 ohm -is the resistance of such a conductor, in which, at a
potential difference of 1 V at its ends, current flows with a force of
1A.

The resistance of the conductor is determined by the geometric
dimensions of the ratio

l
R   , (37.2)
S

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