in parallel with the voltmeter, the readings of the latter decrease
= 2.0 times, whereas the readings of the ammeter increase the
same number of times. Find the voltmeter readings after the con-
nection of the resistance.
3.174. Find a potential difference cp, — cp^2 between points^1 and 2
of the circuit shown in Fig. 3.39 if R^1 = 10 52, R2 = 20 Q, =
= 5.0 V, and F, = 2.0 V. The internal resist-
ances of the current sources are negligible.^ R,^ S/
3.175. Two sources of current of equal emf
are connected in series and have different 1 2
internal resistances R 1 and R^2. (R^2 >^111 ).
Find the external resistance R at which the^62
potential difference across the terminals of one
of the sources (which one in particular?) be-^ Fig. 3.39.
comes equal to zero.
3.176. N sources of current with different emf's are connected
as shown in Fig. 3.40. The emf's of the sources are proportional to61 ,161
A l lI
A 5 I62 ,L____,R
2
'i ' 'Fig. 3.40. Fig. 3.41.their internal resistances, i.e. g = aR, where a is an assigned con-
stant. The lead wire resistance is negligible. Find:
(a) the current in the circuit;
(b) the potential difference between points A and B dividing
the circuit in n and N — rt links.
3.177. In the circuit shown in Fig. 3.41 the sources have emf's
F (^1) = 1.0 V and F 2 = 2.5 V and the resistances have the values
Ri = 10 5.2 and R 2 = 20 52. The internal resistances of the sources
are negligible. Find a potential difference WA — (pB between the
plates A and B of the capacitor C.
3.178. In the circuit shown in Fig. 3.42 the emf of the source is
equal to e = 5.0 V and the resistances are equal to RI = 4.0 El
and 11 2 = 6.0 52. The internal resistance of the source equals R =
= 0.10 52. Find the currents flowing through the resistances R 1
and R 2.
3.179. Fig. 3.43 illustrates a potentiometric circuit by means of
which we can vary a voltage V applied to a certain device possessing
a resistance R. The potentiometer has a length 1 and a resistance
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