IPH402S - INTRODUCTION TO PHYSICS B - 1ST OPP - NOV 2022


IPH402S - INTRODUCTION TO PHYSICS B - 1ST OPP - NOV 2022



1 Pages 1-10

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nAmlBIA unlVERSITY
OF SCIEnCE Ano TECHn OLOGY
FACULTYOF ENGINEERING
lnSTEM
QUALIFICATION:INTRODUCTIONTO SCIENCE,TECHNOLOGY,ENGINEERINGAND MATHEMATICS
QUALIFICATIONCODE: 04STEM
LEVEL: 4
COURSECODE: IPH402S
COURSENAME: INTRODUCTIONTO PHYSICSB
SESSION:
NOVEMBER 2022
PAPER:
N/A
DURATION: 3 HOURS
MARKS:
100
FIRSTOPPORTUNITY 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 FINALANSWERSmust be rounded off to THREEDECIMALPLACES.
7. All CONSTANTVALUESand FORMULAoSn page 9.
THIS QUESTION PAPERCONSISTSOF 9 PAGES(Excludingthis front page)

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SECTION A-TOTAL MARKS 30
This section consists of ten (10) questions. Choose the correct answer and clearly indicate
your answer on your answer sheet. Answer all the questions.
QUESTION 1
[2]
What is the difference between a transvers wave and a longitudinal wave?
(a)
medium particles do not vibrate in the same direction
(b)
sound waves are transverse waves
(c)
all EM radiation are examples of longitudinal waves
(d)
only longitudinal waves are progressive eaves
QUESTION 2
[4]
What is the effective capacitance of the combination of capacitors shown in Figure 1?
3µF
4~
I
I
wµF
2µF
(a)
18 µF
(b) 0.833 µF
(c)
5 µF
(d)
1.515 µF
8V
Figure 1
QUESTION 3
[4]
A copper wire of cross-sectional area 2 mm2 carries a current of 10 A. How many electrons
pass through the wire in half an hour?
(a)
6.25 X 1019
(b)
1.13 X 1023
(c)
2.88 X 10-lS
(d)
18 000
1

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QUESTION4
[2]
Choose the correct statement:
{a) there is a slight delay in the flow of electric current as soon as the switch is closed
(b) charged particles in electrolytes include electrons
(c) current can be seen as the flow of protons
{d) only electrons carry the elementary charge
QUESTION5
(4]
Four cells, each with an emf of 2 V and an internal resistance of 0.2 O are connected in
parallel to each other and to one an external resistor of 2 0. Calculate the total current.
(a)
40 A
41
{b)
41 A
40
(c) ~A
7
(d) 20 A
7
QUESTION 6
[2]
Choose the correct statement:
(a)
the right hand grip rule is used to determine current in a straight wire
(b)
the right hand rule is used to determine current in a straight wire
(c)
the right hand grip rule determines the magnetic field around a straight conductor
(d)
the right hand rule determines the magnetic field around a straight conductor
QUESTION7
(4]
A 98.1 N piece of iron has an apparent mass of 9.0094 kg when submerged in an unknown
liquid. What is the name of the liquid?
(a)
water
(b)
alcohol
(c)
oil
(d)
seawater
2

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QUESTION 8
[2]
A fast-moving fire truck emits an 880 Hz siren. The pitch heard by a stationary observer,
changes by 56 Hz. The observed frequency while the truck is receding is:
(a)
880 Hz
(b)
56 Hz
(c)
936 Hz
(d)
824 Hz
QUESTION 9
[4]
A step- down transformer has a turns ratio of 12:4. When an alternating pd of 0.3 kV is
connected to the primary coil, a current of 30 mA flows in it. Determine the current in the
secondary coil if the percentage power loss in the transformer is 10 %.
(a)
81 mA
(b)
90 mA
(c)
0.9 mA
(d)
27 mA
QUESTION 10
[2]
A decay graph does not have a straight line because:
(a)
the same number of particles decay with every half life
(b)
the sample size decrease with the same amount every half life
(c)
the portion of undecayed particles decrease after every decay period
(d)
the half-life does not remain the same throughout the decay process
3

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SECTION B -TOTAL MARKS 70
This Section consists of six (6) questions. Answer ALL the questions.
QUESTION 11
[10]
11.1 Answer questions 11.1.1 to 11.1.3 with regards to Figure 2.
Figure 2
11.1.1 What effect is depicted in Figure 2?
(1)
11.1.2 Will the observer in Figure 2 hear a lower or higher frequency? Give a reason for
your answer.
(2)
11.1.3 Determine the speed with which the source is moving if the observer hears
the frequencies 800 Hz and 900 Hz.
(4)
11.2 Determine the speed of the wave from Figure 3.
(3)
50
I ['-.
40
\\
E5 30 -
'\\
\\
3 20
t: 10
I\\.
"'-.~v
/ V ---'-\\-
/
i\\
"' v-
/
/
i\\
/
./
--- ' "\\.
/
"- /
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10
Timo (s)
50
r'\\ 40
Ig 30
/
V
I \\ c0..
B
20 - /
t: 10
\\
'-../
i
I
I
I\\
\\
\\
\\. J
/""'r\\
I\\
I\\ I
I
'
\\
I
'- /
\\
\\
~/
J
I
0
10
20
30
40
50
60
70
80
90
100
HorizontalPosltiOn(m)
Figure 3
4

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QUESTION 12
[12]
12.1 In which case(s) of objects placed in a fluid will Vobjec=t VdisplacedE?xplain.
(2)
12.2 State two characteristics of an ideal fluid.
(2)
12.3 A piece of dolomite rock with a density of 2.9 g/cm 3 is placed in a graduated
cylinder filled with seawater, see Figure 4. The level of the seawater rises to 68 ml.
Determine the apparent mass of the stone in the seawater.
(4)
101
60~
so~-g:.
.,.
Figure 4
12.4 The cylinder in Figure 4 is emptied, the rock is removed and then filled
with alcohol using a plastic tube with a very small diameter. If it takes 2 minutes
and 37 seconds to fill to the halfway mark, what is the mass flow rate?
(2)
12.5 At what velocity does the alcohol flow with the tube having a diameter of 3 mm. (2)
5

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QUESTION 13
[16]
13.1 Discuss what you understand with the emf voltage measured in a circuit and
electrical energy.
(2)
13.2 Define electrical power.
(1)
13.3 Determine currents lis, 112 and 136 in Figure 5 using Kirchhoff's laws.
(9)
r-18.0V
/)8 s.oon
s.oon
p
11.on
12.0V
+
7.oon
s.oon
Figure 5
+
36.0V
13.4 How do the plates of the capacitor become positive and negatively charged? (2)
13.5 Calculate the total charge stored on two capacitors connected in parallel. The two
capacitors are 70 µF and 120 µF and are connected to a 20 V supply.
(2)
6

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QUESTION 14
[14]
14.1 How would you use the right-hand grip rule?
{2)
14.2 What will happen in a piece of metal wire that is moved perpendicular to a
magnetic field?
(2)
14.3 How is it possible for current to flow in the secondary coil of a transformer
without any physical connection to the primary coil?
(2)
14.4 Answer questions 14.4.1 to 14.4.3 with reference to Figure 6.
Figure 6
14.4.1 Is this a step-up or step-down transformer? Give a reason for your answer.
{3)
14.4.2 Input voltage= 220 V. The turns on the two coils are 2800 and 700.
Determine Vs.
(1)
14.4.3 With the resistor= 660 0 and the efficiency of the transformer 78 %,
determine the current in the primary coil.
(4)
7

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QUESTION 15
[10)
15.1 Distinguish between the terms nucleon and nuclide.
(2)
15.2 Why do the alpha and beta particles have such different masses?
(2)
15.3 After 966 days 99.21875 % of a sample of a radioactive element has undergone
decay. Use a decay table to determine the number of half-lives and the time for
one half life. Identify the element from the constants on page 9.
(6)
QUESTION 16
[8]
16.1 What is a photon?
(1)
16.2 Briefly describe the photo electric effect.
(2)
16.3 When radiation with wavelength 440 nm is used during the photo electric effect,
electrons with a velocity of 1.6 x 105 m/s is observed. Identify the material looking
at the work functions on page 9.
{5)
8

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LISTOF CONSTANTS:
g = 9.81 m/s 2
density of water= 1000 kg/m 3
speed of sound in the air= 340 m/s
speed of light in vacuum = 3 x 108 m/s
mass of electron = 9.1 x 10-31 kg
density of iron= 7874 kg/m 3
density of seawater = 1023 kg/m 3
1 ml= 1 cm3
Radioactive element
Cadmium
Cobalt-57
Cecium
Half life (days)
463
271
138
Material
Sodium
Zinc
Potassium
Work function (eV)
2.75
4.3
2
density of wood = 530 kg/m 3
density of copper= 8.9 g/cm 3
1 eV = 1.6 x 10·19 J
Planck constant= 6.626 x 10-34 Js
charge of electron=l.6x10· 19 C
density of alcohol = 780 kg/m 3
density of oil = 950 kg/m 3
List of equations
v=J)..
FB =WI
= A1v1 A2v2
J:=J(v:uJ
R=p- A
L
E =hf =¢+KE
P=F
A
p=- m
V
0=!_t
+ fc,=!(v_u J
C=Q
V
Np :N, =VP:V,
P=pgh
=- = V
flow rate
Av
t
power= VJ
emf= (lrRr) + (ITrT)
= powerp powers
9

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