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IPH401S - INTRODUCTION TO PHYSICS B - 2ND OPP - JAN 2020 |
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NAMIBIA UNIVERSITY
OF SCIENCE AND TECHNOLOGY
FACULTY OF ENGINEERING
InSTEM
QUALIFICATION: INTRODUCTION TO SCIENCE, TECHNOLOGY, ENGINEERING AND MATHEMATICS
QUALIFICATION CODE: O4STEM
LEVEL: 4
COURSE CODE: |IPH402S
COURSE NAME: INTRODUCTION TO PHYSICS B
SESSION:
JANUARY 2020
PAPER:
N/A
DURATION:
3 HOURS
MARKS:
100
SECOND OPPORTUNITY EXAMINATION QUESTION PAPER
EXAMINER(S)
Ms Ilana Malan
Ms Oksana Kachepa
MODERATOR:
Mr Anthony Apata
INSTRUCTIONS
1. Answer all questions.
2. Write all the answers in ink.
3. No books, notes, correction fluid (Tippex) or cell phones allowed.
4. Pocket calculators are allowed.
5. You are not allowed to borrow or lend any equipment or stationary.
6. All FINALANSWERS must be rounded off to THREE DECIMAL PLACES.
7. All CONSTANT VALUES and FORMULAS on page 12.
8. Periodic Table on page 13.
THIS QUESTION PAPER CONSISTS OF 13 PAGES (Excluding this front page)
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SECTION A — TOTAL MARKS 30
This section consists of nine questions. Choose the correct answer and clearly indicate your
answer on your answer sheet.
Question 1
[4]
The primary coil of the transformer in Figure 1 has 600 turns. How many turns are on the
secondary?
primary coil
600 turns
240V ~
:
secondary coil
:
12V lamp
(a)
12
(b)
20
(c)
30
(d)
50
Figure 1
Question 2
[4]
At a depth of 12.5 m of a chemical solvent, the bottom of the storage tank due to the solvent
was 306 kPa. Calculate the density of the solvent.
(a) 2.495.413 kg/m?
(b)
2.495 kg/m?
(c)
2 495.413 kg/cm?
(d)
2.495 kg/cm?
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Question 3
[4]
Determine the total capacitance between points A and B in Figure 2 below:
5four
eeCg = 10uF
460uF
8
Figure 2
(a)
420 uF
(b)
20.075 UF
(c)
8 UF
(d)
120 UF
Question 4
[2]
A swimmer floating in the ocean floats up and down as the waves pass by her. The distance the
swimmer moves up and down would be:
(a)
twice the amplitude
(b)
the wavelength
(c)
the amplitude
(d)
twice the wavelength
Question 5
[2]
Photons that are emitted during radioactive decay are called:
(a)
alpha rays
(b)
beta rays
(c)
gamma rays
(d)
x-rays
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Question 6
[2]
| waves A and B in Figure 3 are superposed, the resultant wave is:
r
al
Figure 3
d)
Question 7
[4]
If 4 x 1078 atoms decay with a half-life of 2.3 years, how many half-lives will it take for
3.9375 x 107° of the atoms to decay?
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Question 8
[4]
A generator produces power for a school. 100 kW of power is produced by the generator
with a potential difference of 10 kV across it. In order to reach the school the current
produced must flow through cables of resistance 0.12 Qm/km. The school is 57 m from
the generator. The power loss in the cables is:
(a)
648 A
(b)
100 A
(c)
12A
(d)
684A
Question 9
[4]
A student hears two echoes when she claps her hands. One echo is 0.5 s after the clap and
the other is 1s after the clap. She decides that the two echoes are from buildings in front of
her. How far apart are the buildings? (speed of sound in air = 340 m/s)
(a)
340 m
(b)
225m
(c)
170 m
(d)
85m
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SECTION B — TOTAL MARKS 70
This section consists of six (6) questions. Answer ALL the questions.
Question 10
[10]
10.1
How would you arrange the long chain molecules in a polaroid filter if you want
to allow only vertical vibrations to pass through the filter?
(1)
102 The grap hs in Figure 4 show information regarding two strings. Answer the questions
10.2.1 — 10.2.4 with regards to Figure 4.
Displacement (cm)
:
a
String A
PV
4DA a L Pia A as L fe.
b=
<a
AAMANAIMN., Displacement (cm)
StringB
b>
Figure 4
5
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10.2.1 String A moves at a speed of 5 m/s. Draw a displacement-distance graph for
string A with three full wavelengths. At time = 0 seconds the wave should have
maximum amplitude. Cleary indicate wavelength.
(5)
10.2.2 String B moves with the same speed as string A. Determine the wavelength for
string B.
(2)
10.2.3 Both waves move through the same size gap. Which string A or B will show the
most diffraction?
(1)
10.2.4 When the two strings are super imposed at t = 10s, will we see constructive or
destructive interference?
(1)
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Question 11
[12]
a4
A cylinder of a solid material is floating in oil (0.93 g/cm?). The diameter of the
cylinder is 7 cm and the height is 19 cm. If 28 % of the object is submerged, what is
the density of the cylinder?
(4)
11.2
Relate viscosity of fluids with friction.
(2)
11.3
One of the properties that can be compared between fluids is that gases have a low
density and liquids a higher density. What property do liquids have that gases do
not have?
(1)
11.4 Define flow rate.
(1)
11.5
During dry season in many places water supply to residential dwellings may be cut
to save the supply in the dams. Many citizens make use of water reservoirs (large
tanks) to store water for domestic use. A family of four uses on average 315 | of water
per day per person. (1 m? = 10001)
11.5.1 How long will a 5000 | tank give them water for?
(1)
11.5.2 How long will it take them to fill the tank after two days of water use if the inlet has
a 40 mm diameter and water is pumped at 700 ml / s?
(3)
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Question 12
[12]
12.1
What does the formula V = energy tell you about PD?
(1)
=
12.2
Answer questions12.2.1 — 12.2.5 with regards to Figure 5. The battery in Figure 5
consist of4 cells connected in parallel. Each cell has an internal resistance of 1363 Q
and emf of 1.5 V. Internal voltage drop is 1.65 V.
eel
I
2.1
F
le
Figure 5
12.2.1 What will P measure? Be specific.
(2)
12.2.2. Write an equation that will denote Kirchhoff’s second law that includes P.
(2)
12.2.3 Determine total current if Ii = lz.
(4)
12.2.4 Determine the total current if the cells were connected in parallel.
(3)
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Question 13
[12]
13.1
Which well known experiment is depicted in Figure 6?
(1)
Ultra violet light
Figure 6
13.2
What did this experiment prove?
(1)
13.3
Differentiate between work function and threshold frequency.
(4)
13.4 The work function of Ca 2.9 eV and that of Pt is 5.6 eV. Light with a frequency of
9 x 10% Hz is incident on both metals.
13.4.1 From which metal surface will an electron be emitted?
(3)
13.4.2 At what velocity does the emitted electron move?
(3)
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Question 14
[8]
14.1
State the effect depicted in Figure 7 and give the definition.
(3)
Figure 7
14.2
What happens to the frequency of the ambulance in Figure 7?
(1)
14.3
Use the graph in Figure 8 below to determine the speed that a train passes a
passenger standing on the platform. (speed of sound in air = 330 m/s)
(4)
221200 |
200
190
180
170
160
150
140
130
120
110
100
30
80
70
60
50
40 |
30
20
10
Frequency-Time (graph)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
18.
Time (s)
Figure 8
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Question 15
[8]
15.1
What is the advantage of transmitting power at high voltage via power lines?
(2)
15.2 A power station generates power for a factory. The 10 MW power must be
delivered to the factory at 40 kV. If the cables have resistance of 5 Q, how much
power must be generated?
(3)
13.3
In a step-up transformer the turns ratio is 3:18. The voltage measure in
the secondary coils is 8000 V with a current of 0.5 A. There is no power loss in
the transformer. What is the current in the primary coil?
(3)
Question 16
[8]
16.1 Write a one equation to illustrate the decay of Thorium-230 that undergoes
radioactive decay by emitting 3 alpha particles and 5 beta particles.
(3)
16.2
What is the meaning of activity when used with regards to radioactivity?
(1)
16.3 A radioactive sample decays and in a time of 43 minutes out of the original sample
of 5000 active particles a total of 4960.9375 undergoes decay. How long is one
half-life? Make use of a table and show your working.
(4)
The End
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Constants and formulas:
103 | kilo |K | 10% | centi |c
10° | Mega | M |} 10° | milli | m
10° | Giga |G | 10° | micro] p
10% | Tera | T | 10° | nano | n
10% | Peta | P | 1077] pico |p
g = 9,81 m/s?
mass of electron=9.1 x 10°31 kg
Planck’s constant = 6.626 x 104 m2kg/s
elementary charge = 1.6 x 10°19
List of equations
v=fa
FF, =W,
Av, = A,v,
vtu
=f
R=p-P —AL
E=hf =$+KE
P=—F
A
p=—
V
Q= 7I
v
J=f vt
C==QV
N,:N,=V,:V,
P=pgh
flow ra=t —V e = Av
t
power =VI
emf =(I,R;,)+(Ipry)
P ower, p—= P power. 8
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