Laboratory Physics 1 (PHYS2205)
BSc, Physics - PHYS
Semester: Second Semester
Level: 200
Year: 2017
School/Faculty:
Science
Department: Physics Lecturer(s): Dr Zambo/ Dr Nana
Course Code: PHYS 2205 Course Title: Laboratory Physics I
Date:
05/08/2017
Hall: Asanji Time: 14:30 – 17:30
Instructions: Answer clearly all questions. Put in box the final result
REPUBLIC OF CAMEROON THE UNIVERSITY OF BAMENDA
Peace-Work-Fatherland P.O. BOX 39 Bambili
Exercise 1 (6 marks)
Give the title of the experiments that you have performed in the Physics laboratory this academic year.
Exercise 2 (40 marks)
1 - Draw a RC circuit supplied by a function generator and set the oscilloscope to measure the total voltage in
channel I (CH.I) and the voltage across the capacitor in channel II.(CH.II)
[4 marks]
2) The two waveforms U1 (across the function generator), and U2 (across the capacitor) are positioned vertically
and are both clearly. Explain the purpose of these controls:
a) Time/div b) Volts/div c) Horizontal position d) Vertical position [4 marks]
3) Determine the amplitudes and the periods of the two signals U1 and U2 [2X4 marks]
t[ms]
4) Determine the phase difference between the two signals U1 and U2 [4 marks]
5) Give the expressions of U1 and U2 in function of time [2+2 marks]
6) Find the average and the root mean squares of U1 [3+3 marks]
7) From your oscilloscope, you add these two signals by pressing the ADD snob. Sketch the graph shown in the
screen of your oscilloscope. [3 marks]
8) You release the ADD snob and press the x-y snob to obtain the curve CH2 as function of CHI Signals. Sketch
the waveform [3 marks]
9) Sketch two other types of electrical signals generated by the function generator [4 marks]
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Exercise 3 (24 marks)
In the lab, you measure the voltage U across two resistors R1=100 Ω and R2 connected either in series or in parallel
and the current I through the resistance.
1) Propose a title to this experiment. [2marks]
The data obtained are shown in the following table:
0. 1.0 2.0
3.0 4.0 5.0
6.0
7.0
8.0
I(mA)
0.00 2.001
4.002
6.001
8.003 10.02
12.03
14.04
16.0
U(V) 9.0
10.0
11.0 12.0 13.0
14.0
I(mA) 18.01
20.02
22.04 24.06 26.0
28.01
2) Using the least square method, we assume that the relation between U and I is in the form: U = aI+ b, where a
and b are defined as:
a =
∑
.
.
∑
(
)
, and b=
−
, with
=
∑
and
=
∑
a) Determine N,
,
,
∑
,
∑
,
∑
[6 marks]
a) Compute a and b. [3+3 marks]
3) Sketch the graph U = aI+ b [4 marks]
4) How have you connected these two resistors? Justify. [2 marks]
5) Deduce the value of the resistance R2 [4 marks]
U(V)
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