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PHY301 COLLECTION OF OLD PAPERS
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Student ID/Login
ID
Name
PVC Name/Code
Exam Center
Date
MID TERM EXAMINATION
SEMESTER Fall (2004)I PHY- 301 CIRCUIT THEORY
Total Marks: 50
Duration: 60 min
Maximum Time Allowed: (1 Hour)
Instructions Please read the following instructions carefully before attempting any question:
All questions are compulsory.
a. This exam consists of One Multiple Choice Questions (MCQ's) ,which carries 5 Marks
and four descriptive questions.
b. Each MCQ carries 1 Marks.
c. While attempting descriptive question do not miss any step so that you could get
better marks.
d. Do not ask about the contents of any question of this examination from anyone.
e. If you think that there is something wrong with any of the questions, attempt it to
the best of your understanding.
f. On the other hand, if you believe that all of the choices provided for a particular
question are the wrong ones, select the one that appears to you as being the least
wrong.
g. The duration of this examination is 60 minutes.
h. This examination is closed book, closed notes, closed neighbors.
i. Do not ask any questions about the contents of this examination from anyone.
j. Draw Circuit diagrams (where necessary) for each step to get maximum score in the
exam.
**WARNING: Please note that Virtual University takes serious note of unfair means.
Anyone found involved in cheating will be given grade `F` in this course.
For Teacher’s use only
Question Q1 Q2 Q3 Q4 Q5 Total Signature Marks
Question No: 1 Marks: 5
For each question given below, encircle the option that in your opinion represents the best/ correct answer. I) When placed close together, a positively charged material and a negatively charged material will
a) Repel b) Become neutral c) Attract d) Exchange charges
II) Potential difference is another term for
a) Energy b) Voltage c) Watt d) Distance of an electron from the nucleus.
III) There is no current in the circuit when
a) A switch is closed b) A switch is open c) There is no voltage d) Answer (a) and (c) e) Answer (b) and (c)
IV) How much resistance is required to limit the current from a 10V battery to 1mA
a) 100Ω b) 1.0 k Ω c) 10 Ω d) 10k Ω
V) Which of the following statements are true concerning the figure below a) R1 and R2 are in series with R3 , R4, and R5
b) R1 and R2 are in series c) R3 , R4, and R5 are in parallel d) The series combination of R1 and R2 ιs in parallel with the series combination of R3 , R4, and R5. e) Answers (b) and (d)
Question No: 2 Marks: 12
Use nodal analysis to find IO in the given network.. Identify and label each node otherwise you will lose your marks. Label circuit diagram properly.
Answer/Solution
We will redraw figure as
At Node 3 V3 = -6V
KCL at Node 1 (V1 + 6)/6 + (V1-V2)/6 =-5mA ------ (A)
KCL at Node 2 (V2 + 6)/6 + (V2-V1)/6 + V2/6= 0 ------- (B)
Solving (A) and (B) we get V2=12/5 = 2.4
Now Io = V2/R =2.4/6 =.4 mA
Question No: 3 Marks: 20
Use Mesh analysis to find currents through all Meshes. Identify and label each mesh otherwise you will lose your marks. Label circuit diagram properly.
Answer/Solution
We will redraw figure as
KVL equation for mesh 1
2+4 I 0 +3 (I -I =1 1 2) 7I1-3I2= -2 -------------------- (1)
Now we will redraw figure for super mesh as
KVL equation for super mesh
1(I 6+3(I =0 -I ) +8I +5I + - I )2 4 3 2 2 1 Simplifying above equation we get
-3I1+9I2+8I3-I4= -6…………….. (2)
KVL equation for Mesh 4
2I +5+3I4+1(I4-I2) =0 4
Simplifying we get -I2+ 6I4= -5…………… (3)
Constraint Equation I3-I2=7 ………….. (4)
From Equation (1) I1= (3I2-2)/7
From Equation (3) I4= (I2-5)/6
From Equation (4) I3=I2+7
Putting the values of I1, I3, I4 in equation (2) & simplifying we get 653I2=-2176
I2= -3.33A I1 = - 1.71A I3 =3.67A I4 =-1.38A
Question No: 4 Marks: 7
Find the power absorbed by the 30kΩ resistor in the circuit below.
Answer/Solution
Writing KVL equation
-12 -30I + 2Vx+ Vx=0
-12+30kI+20kI+10kI=0 I =200µA
Therefore
P30k=I2*R = (200x 10-6)2*30
= 1.2MW
Question No: 5 Marks: 6
(a) Two resistors R1 and R2 of 5Ω each and R3 of 10 Ω are in series. How much is RT. If we applied 80 V source across the series string, how much is the current in R3. Answer/Solution
RT = R1+R2+R3 = 5+5+10 = 20Ω
I = VT/RT = 80/ 20 = 4A
(b) Define Potential difference. What is Conventional Current? Answer/Solution Potential difference The potential difference is defined as the amount of work per charge needed to move electric charge from the second point to the first, or equivalently, the amount of work that unit charge flowing from the first point to the second can perform. In the SI system of units, potential difference, electrical potential and electromotive force are measured in volts, leading to the commonly used term voltage and the symbol V.
OR
Current flowing in a conductor is due to a potential difference between its ends. Electrons move from a point of less positive potential to more positive potential and the current flows in the opposite direction. The SI unit of potential difference is the volt (V).
Volts are the measure of Potential Difference across circuit elements (battery, resistor etc.).
Conventional Current The motion of positive charge, in the opposite direction from electron flow, is considered as conventional current. Electricity was known of long before Benjamin Franklin. It was not understood very well, but it was known of. Scientists knew there were two kinds of electric charge. They knew there was electric current. Scientists believed that the opposite charges moved similarly in opposite directions. They defined one as positive and one as negative. They defined current to be in the direction of the positive charges. Later, they learned of their mistake. Only the negative charges move freely in conductors. Electrons had been defined as the negative charges. Current had been defined "backwards". It was too late to redefine all of electrical physics, so the inconvenience holds to this day. The direction that the electrons move is opposite the direction that current points. Because of how electricity works, it isn't much of a problem. Negative charge moving to the left through a wire has the same effect as positive charge moving to the right. So long as the total charge in the wire (protons and electrons) remains balanced, no trouble occurs.
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FINAL TERM EXAMINATION SEMESTER (Fall 2004)
PHY-301 CIRCUIT THEORY
Total Marks: 50 Duration: 120min
Student ID/Login ID
Name
PVC Name/Code
Exam Center
Date 11-02-2005
Instructions
Maximum Time Allowed: (2 Hour)
Please read the following instructions carefully bM
CQ carries 1 Marks .
c. While attempting descriptive question do not miss any step so that you could get
better marks.
d. Do not ask about the contents of any question of this examination from anyone.
e. If you think that there is something wrong with any of the questions, attempt it to
the best of your understanding.
g. On the other hand, if you believe that all of the choices provided for a particular
question are the wrong ones, select the one that appears to you as being the least
wrong.
h. The duration of this examination is 120 minutes.
i. This examination is closed book, closed notes, closed neighbors.
j. Do not ask any questions about the contents of this examination from anyone.
k. Draw Circuit diagrams (where necessary) for each step.
**WARNING: Please note that Virtual University takes serious note of unfair means. Anyone found involved in cheating will be given grade `F` in this course.
For Teacher’s use only Question Q1 Q2 Q3 Q4 Q5 Total Signature Marks
Question No: 1 Marks: 5
For each question given below, encircle the option that in your opinion represents the best/ correct answer.
I) Choose the correct term, an electronic device that is capable of storing a charge for a long time. a) Transistor b) Semi-conductor c) Capacitor d) Diode
II) The unit of electrical potential difference is a) watt b) Volt c) ohm d) ampere
III) Resistances R1 and R2 are in series with 90 V applied. If V1 is 30 V then V2 must be a) 30 V b) 90 V c) 45 V d) 60 V
IV) In an N –type semiconductor materials, the majority carrier are a) Holes b) Electrons c) Ions
d) Protons V) When a current of 20 milliamps flows through a 50 ohm resistor the voltage drop across the resistor will be:
a) 100 mill volts b) 10 mill volts c) 1 volt d) 10 volts
Question No: 2 Marks: 15
Use Mesh analysis to find currents through all Meshes. Label circuit diagram properly. Write each step of the calculation to get maximum marks.
Question No: 3 Marks: 12
Find Vo in the network using Source Transformation. Draw and label the circuit diagram of each step, otherwise you will lose your marks. Write each step of calculation to get maximum marks.
Question No: 4 Marks: 10
a) How does transistor work? b) What is PN-junction diode.
Question No: 5 Marks: 8
The transistor in the circuit below has a very high β. Find VE and VC for VB (a) +6V, (b) +2V, and (c) 0V. Assume VBE ≅ 0.7 V.
PHY301 Final Paper Page 1 of 4
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PHY301 Circuit Theory Final Term Examination - July 2003
Session -1
TIME ALLOWED: 150 Minutes TOTAL MARKS: 66 Please read the following instructions carefully before attempting any of the questions:
a. All questions are compulsory. b. This exam consists of 10 Multiple Choice Questions (MCQ's); one question is for filling in the
blanks which carries 20 Marks and three descriptive questions. c. Each MCQ carries 1 Marks. d. Fill in the blanks question carries 20 Marks. e. While attempting descriptive question do not miss any step so that you could get better marks. f. You can type the answer of descriptive question in Ms Word and then copy it in the software
provided to you by the Virtual University. All the figures and formats should also be made in the Ms Word and then be copied in the provided software. For figures you can use MS PAINT.
g. When you have copied your answer in the software. Do not worry if it's format changes. h. Save your answer before proceeding to the next question. i. Do not ask about the contents of any question of this examination from anyone. j. If you think that there is something wrong with any of the questions, attempt it to the best of
your understanding. k. On the other hand, if you believe that all of the choices provided for a particular question are
the wrong ones, select the one that appears to you as being the least wrong. l. Do not click the "Finish" button" while solving your paper. Once you clicked the "finish" button,
you will not be able to access your paper again. Click it at the end of your paper. That means you have submitted your complete paper.
Total Questions 14
Q.No 1 International system of units is built upon how many basic units.
o 8 o 9 o 10 o 7
Q.No 2 Absolute zero corresponds to
o 0oC
o 32oC o 273K o 0 K
Q.No 3
Two unlike charges will o Attract o Repel o None of the above
Q.No 4
PHY301 Final Paper Page 2 of 4
With zero potential difference across a wire, the current will be o Maximum o Depends upon the wire o Zero o None of the above
Q.No 5
The opposition which limits the current is called o Conductance o Resistance o Resistivity o Conductivity
Q.No 6
In the above circuit value of Io will be o 2mA o 1A o 2A o 1mA
Q.No 7
The process whereby charged particles move under the influence of electric field is called
o Current o Voltage o Drift o None of the above
Q.No 8 Phosphorus is a -------- element
o Pentavalent o Trivalent o Hexavalent o None of the above
Q.No 9
The current flows through the diode when it is reverse biased is called o Leakage current o Breakdown current o Saturation current o None of the above
Q.No 10 The resistance offered by the inductor is called
o Inductance o Capacitance o Resistivity o None of the above
Q.No 11
Fill in the blanks.
PHY301 Final Paper Page 3 of 4
All questions carry 2 marks each (i) Mole is a unit of ------------ (ii) 1 Mega Ohm is equal to ----------- ohms. (iii) Hydrogen has an atomic no ---------------. (iv) Electron valance is the no of electron in the incomplete -------- shell. (v) The voltage drop across a short circuit is --------- . (vi) The current that results from the diffusion of charged particles is called -------
current. (vii) Doped silicon in which majority of charge carriers are negatively charged
electrons is called ---------- type. (viii) The windings of transformer connected to the load is called ---------windings. (ix) One diode can be used as a ------- wave rectifier. (x) Analyze the following circuit
Req = --------------. Q.No 12
Carry out analysis of the circuit to calculate voltage at all nodes and current through all branches. Please show all steps for the calculation. [20]
Q.No 13
(a) Find the resultant inductance of the circuit. Please show all steps for the calculation.
(b) Define the following sources [4] (i) Independent voltage source. (ii) Voltage dependent current source.
Q.No 14
Calculate the current through the circuit. Please show all steps for the calculation. [10]
PHY301 Final Paper Page 4 of 4
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Student ID/Login
ID
Name
PVC Name/Code
Exam Center
Date 21-07-2005
FINAL TERM EXAMINATION
SEMESTER (Spring 2005)I PHY-301 CIRCUIT THEORY
Total Marks: 50
Duration: 120min
Maximum Time Allowed: (2 Hour)
Instructions Please read the following instructions carefully before attempting any question:
All questions are compulsory.
a. This exam consists of One Multiple Choice Questions (MCQ's) ,which carries 5 Marks
and four descriptive questions.
b. Each MCQ carries 1 Marks .
c. While attempting descriptive question do not miss any step so that you could get
better marks.
d. Do not ask about the contents of any question of this examination from anyone.
e. If you think that there is something wrong with any of the questions, attempt it to
the best of your understanding.
f. On the other hand, if you believe that all of the choices provided for a particular
question are the wrong ones, select the one that appears to you as being the least
wrong.
g. The duration of this examination is 120 minutes.
h. This examination is closed book, closed notes, closed neighbors.
i. Do not ask any questions about the contents of this examination from anyone.
j. Draw Circuit diagrams (where necessary) for each step.
**WARNING: Please note that Virtual University takes serious note of unfair means. Anyone found involved in cheating will be given grade `F` in this course.
For Teacher’s use only
Question Q1 Q2 Q3 Q4 Q5 Total Signature
Marks
Question No: 1 Marks: 5
For each question given below, encircle the option that in your opinion represents the best/ correct answer.
1)The resistance in a short circuit is a) Large b) small c) Zero d) None of the above
2) If one of the diode in a full –wave bridge rectifier is open, the out put is a) 0V b) One –fourth the amplitude of the input voltage c) a half –wave rectified voltage d) a 120 HZ voltage
3) The charge in motion is called a) Voltage b) current c) intensity d) Coulomb
4) The emitter current is always a) Greater than base current b) Less than collector current c) Greater than collector current d) Small than base current
5) In PNP transistor, the P-regions are a) Base and emitter b) Base and collector c) emitter and collector d) All of the above
Question No: 2 Marks: 15
For the circuit shown in the figure below, all the resistors are given in Ohms; (a) Find the equivalent resistance seen by the supply (b) Find the power in the source and the 10Ω resistor. Draw the circuit diagram of each step otherwise you will lose your marks. Write each step of the calculation to get maximum marks and also mention the units of each derived value.
Question No: 3 Marks: 15
Using superposition find
a) the current through the 3-Ω resistor due to the voltage source b) the current through the 3-Ω resistor due to the current source c) the power delivered to the 3-Ω resistor
Draw and label the circuit diagram, otherwise you will lose your marks. Write each step of calculation and also mention the units of each derived value.
Question No: 4 Marks: 5
What is tunnel diode? Draw the graphic symbol of tunnel diode. Describe the negative resistance operating region of the tunnel diode. Include the relationship between diode forward current and forward voltage.
Question No: 5 Marks: 10
For the NPN bipolar transistor, assume that the VBE(on) = 0.7V. (a) If VCC = 5V, solve for IB, IC, and IE. Assume that β = 100. Be sure to justify each step that you take. (b) Resolve this using β=200 Be sure to justify each step that you take, also mention the units of each derived
value
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Student ID/Login
ID
Name
PVC Name/Code
Exam Center
Date 21-August-2007
MID TERM EXAMINATION MID TERM EXAMINATION
SEMESTER (Summer 2007) I SEMESTER (Summer 2007) I
PHY- 301 CIRCUIT THEORY PHY- 301 CIRCUIT THEORY
Total Marks: 40 Total Marks: 40
Duration: 120 min Duration: 120 min
Maximum Time Allowed: (1 Hour)
Instructions Please read the following instructions carefully before attempting any question:
All questions are compulsory.
¾ This exam consists of One Multiple Choice Questions (MCQ's) ,which carries 6 Marks
and three descriptive questions.
¾ While attempting descriptive question do not miss any step so that you could get
better marks.
¾ If you think that there is something wrong with any of the questions, attempt it to
the best of your understanding.
¾ On the other hand, if you believe that all of the choices provided for a particular
question are the wrong ones, select the one that appears to you as being the least
wrong.
¾ This examination is closed book, closed notes and closed neighbors.
¾ Do not ask any question about the contents of this examination from anyone.
¾ Draw Circuit diagrams (where necessary) for each step to get maximum score in
the exam.
**WARNING: Please note that Virtual University takes serious note of unfair means. Anyone found involved in cheating will be given grade `F` in this course.
For Teacher’s use only
Question Q1 Q2 Q3 Q4 Total Signature Marks
Question No: 1 Marks: 6
For each question given below, encircle the option that in your opinion represents the best/ correct answer. Encircle only “ONE” option. I) Current divider is used when
a) two or more resistances are in series to a voltage source b) two or more resistances are in parallel to a current source c) One resistance in parallel to current source d) None of above
II) 10Ω and 5Ω resistances are in series. If current through 5Ω is 5 ampere , current of 10Ω will be a) 10A b) 20A c) 5A d) 40
III) If the current arrow is directed into the + marked terminal of an element, then p=vi yields the………………...
a) absorbed power b) emitted power c) loss power d) high power
IV) When a proton and an electron come close together they a) repel each other b) become neutral c) have no effect d) attract each other
V) The resistance of an open circuit is a) high b) low c) zero d) infinite
VI) The current passing through the conductor is directly proportional to the voltage provided temperature remains constant, is the statement of
a) Kirchhoff’s law b) Newton’s law c) Ohm’s law d) Pascal law
Question No: 2 Marks: 8
(a) Why does a person wearing rubber shoes do not get electric shock when touching a naked conducting wire.
Marks=3 (b) Find voltage across 20kΩ in the figure below.
Marks =5 Question No: 3 Marks: 14
Use nodal analysis to find VO in the network given below. Identify and label each node otherwise you will lose your marks. Write each step of the calculation to get maximum marks and also mention the units of each derived value.
Question No: 4 Marks: 12
Use Mesh analysis to find Current through each mesh in the given network. Identify and label each mesh and also show each step of calculation otherwise you will lose your marks and also mention the units of each derived value. .
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Students FINALTERM EXAMINATION
SPRING 2006
PHY301 - CIRCUIT THEORY (Session - 1 )
Marks: 60
Time: 120min
StudentID/LoginID:
Student Name:
Center Name/Code:
Exam Date: Saturday, August 19, 2006
Instructions
Please read the following instructions carefully before attempting any question:
All questions are compulsory.
¾ This exam consists of One Multiple Choice Questions (MCQ's) ,which
carries 10 Marks and four descriptive questions.
¾ While attempting descriptive question do not miss any step so that you
could get better marks.
¾ Do not ask about the contents of any question of this examination from
anyone.
¾ This examination is closed book, closed notes and closed neighbors.
¾ Do not ask any question about the contents of this examination from
anyone.
¾ Draw Circuit diagrams (where necessary) for each step to get
maximum score in the exam.
**WARNING: Please note that Virtual University takes serious note of unfair means. Anyone found involved in cheating will be given grade `F` in this course.
For Teacher's use only Question 1 2 3 4 5 6 7 8 9 10 Total
Marks
Question 11 12 13 14
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Marks
Question No: 1 ( Marks: 1 ) - Please choose one Superposition theorem can be applied only to circuit having …….. elements.
Non-linear
Passive
Linear bilateral
Resistive
Question No: 2 ( Marks: 1 ) - Please choose one The output of a half wave rectifier is suitable only for ..........
Running car diodes
Charging batteries
Diode rating
Purity of power output
Question No: 3 ( Marks: 1 ) - Please choose one While calculating Rth current sources in the circuit are
Replaced by opens
Replaced indirect voltage
Replaced by short
Replaced DC voltage
Question No: 4 ( Marks: 1 ) - Please choose one
In parallel circuits all components must
have the same value
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have same potential difference
carry the same current
be switched ON & OFF simultaneously
Question No: 5 ( Marks: 1 ) - Please choose one
The clipping level is primarily determined by
shape of the input waveform
value of the resistor
battery voltage
knee voltage of the diode
Question No: 6 ( Marks: 1 ) - Please choose one
The depletion region of a P-N junction is formed
During the manufacturing
When forward bias is applied to it
Under reverse bias
When its temperature is reduced
Question No: 7 ( Marks: 1 ) - Please choose one
The dc load line of a transistor can be drawn if we know its cut off and ……. points
active
saturation
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quiescent
None of them
Question No: 8 ( Marks: 1 ) - Please choose one The filter is simply a capacitor connected in ----------- with the load resistance.
series
parallel
we can use it in series as well as in parallel
none of them
Question No: 9 ( Marks: 1 ) - Please choose one Zener diode is operated in the ……. Region
cut-off
forward
breakdown
saturation
Question No: 10 ( Marks: 1 ) - Please choose one
A tunnel diode is always biased
By dc source
In the reverse direction
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In the middle of its negative resistance region
None of them
Question No: 11 ( Marks: 15 ) Use nodal analysis to find out the power supplied by current source in the network given below. Identify and label each node otherwise you will lose your marks. Write each step of the calculation to get maximum marks and also mention the units of each derived value.
Question No: 12 ( Marks: 10 ) Find VO in the network given below using Thevenin’s theorem. Show each step of calculation otherwise you will lose your marks. Draw and label the circuit diagram of each step and also mention the units of each derived value.
Question No: 13 ( Marks: 10 )
Find IO in the network given below using Norton’s theorem. Show each step of calculation otherwise you will lose your marks. Draw and label the circuit diagram of each step and also mention the units of each derived value.
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Question No: 14 ( Marks: 15 )
(a) Measurement on the circuit below produces labeled voltages as indicated. Find the value of β for the given circuit. Marks=6
(b) For the circuit shown in the figure below, find the emitter, base, and collector voltages and currents. Use β= 32, but assume |VBE| = 0.7V independent of current level. Marks: 9
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