Exercise 3: Laws of voltage and current (12 pts)
The adjacent diagram is a portion of an electric circuit:
Given I=10 A, L =5 A, L = 3 A, la = 1 A, and is = 3A.
Li, L2, ..., and Ls are lamps.
The points A and B are connected to a battery.
1
itoa
is
A. Motion of the electrons:
a) Specify whether B is connected to the
positive or to the negative pole of the battery.
b) Calculate the charge and the number of electrons
that enter into junction A
during 2 minutes
16
C 3A
B
D
Lo
IR
B. Grouping of lamps:
a) Name the two lamps which are connected in series.
b) Name the two lamps which are connected in parallel. Are these two lamps identical? why?
CJunction ule:
al Specify the value of the current Is that flows out of the junction B.
b) Calculate the value of the current 12.
c) Determine the direction and the value of the current 16
d) Deduce the value of the current 17.
D. Laws of voltages:
Given: UA= 12 V, UE= -2 V, UED = 1 V and Uac=5.5 V.
a) Calculate UAE, UAD, Ucend Up
b) Calculate UCD. Specify whether the lamps L3 and Ls are identical.
o) Draw the branch BE and show the connections of an oscilloscope so that it displays Urg. ground to
in) The luminous line, initially at Y=0, is displaced downward. Justify.
iii) Calculate the number of division y by which the luminous line is displaced. (given Sv = 1V/div)
phrase A