Hello friends,
This was a pattern of VVDN paper held on 29-06-13 in Vector Bangalore.
3 sections,total 60 ques,90 minutes
I- 20 questions on aptitude.
II-20 questions on electronics.
III-20 questions on C.
The level of questions was average.
I am providing the questions of Electronics Section.
1-Unit of magnetic field.
In SI units, B is measured in teslas (symbol: T) and correspondingly ΦB (magnetic flux) is measured in webers (symbol: Wb) so that a flux density of 1 Wb/m2 is 1 tesla. The SI unit of tesla is equivalent to (newton·second)/(coulomb·metre). In Gaussian-cgs units, B is measured in gauss (symbol: G). (The conversion is 1 T = 10,000 G.) The H-field is measured in amperes per metre (A/m) in SI units, and in oersteds (Oe) in cgs units.
2-Unit of resistivity.
3-Thevenin equivalent of the circuit.
4-find the voltage across the load,the figure will be provided.
5-find the equivalent capacitance,through the figure provided.
6-find the equivalent gate,gate will be made by BJT.
7-find the equivalent gate,gate will be made by Diode.
8-One multiplexer question.
9-value of charge on electron.
The electron (symbol: e−) is a subatomic particle with a negative elementary electric charge.Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure.The electron has a mass that is approximately 1/1836 that of the proton.Quantum mechanical properties of the electron include an intrinsic angular momentum (spin) of a half-integer value in units of ħ, which means that it is a fermion. Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Electrons also have properties of both particles and waves, and so can collide with other particles and can be diffracted like light. Experiments with electrons best demonstrate this duality because electrons have a tiny mass.
−1.602176565(35)×10−19 C
10-2 more question regarding the charge.
11-1 que of BJT circuit.
12-Effect of temperature on conductivity of the semiconductor.
Let’s Consider the effect of increasing the temperature on the conductivity of semiconductors.
Let's look at the factors that go into conductivity of a semiconductor and consider how each of these are affected:
Conclusion:
The electrical conductivity of a semiconductor will increase exponentially with an increase in temperature!
We can graph this equation on log vs. 1/T axes to get a linear plot (as with all Arrhenius type equations):
13-Effect of temperature on conductivity of the conductor.
How Does Temperature Affect the Conductivity of a Conductor?
Let’s Consider the effect of increasing the temperature on the conductivity of conductors.
Let's look at the factors that go into conductivity and consider how each of these are affected:
Conclusion:
The electrical conductivity of a conductor will decrease with an increase in temperature!
The relationship is not linear, however, if we consider the resistivity, which is the reciprocal of conductivity, we do get a linear relationship:
The electron (symbol: e−) is a subatomic particle with a negative elementary electric charge.Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure.The electron has a mass that is approximately 1/1836 that of the proton.Quantum mechanical properties of the electron include an intrinsic angular momentum (spin) of a half-integer value in units of ħ, which means that it is a fermion. Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Electrons also have properties of both particles and waves, and so can collide with other particles and can be diffracted like light. Experiments with electrons best demonstrate this duality because electrons have a tiny mass.
−1.602176565(35)×10−19 C
14-Find the resistance of the long wire(I dont know the question exactly)
15-1 que on transformer(simple)
16-1 que on steady state
an unvarying condition in a physical process, especially as in the theory that the universe is eternal and maintained by constant creation of matter
17-1 que on majority carriers & minority carriers in BJT.
Hope this will be helpful for you & best of luck.
This was a pattern of VVDN paper held on 29-06-13 in Vector Bangalore.
3 sections,total 60 ques,90 minutes
I- 20 questions on aptitude.
II-20 questions on electronics.
III-20 questions on C.
The level of questions was average.
I am providing the questions of Electronics Section.
1-Unit of magnetic field.
In SI units, B is measured in teslas (symbol: T) and correspondingly ΦB (magnetic flux) is measured in webers (symbol: Wb) so that a flux density of 1 Wb/m2 is 1 tesla. The SI unit of tesla is equivalent to (newton·second)/(coulomb·metre). In Gaussian-cgs units, B is measured in gauss (symbol: G). (The conversion is 1 T = 10,000 G.) The H-field is measured in amperes per metre (A/m) in SI units, and in oersteds (Oe) in cgs units.
2-Unit of resistivity.
Ampere - A
The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2 x 10-7 Newton per meter of length.
Electric current is the same as electric quantity in movement, or quantity per unit time, expressed like
I = dq / dt
where
I = electric current (ampere, A)
dq = electric quantity (coulomb, C)
dt = time (s)
Coulomb - C
The standard unit of quantity in electrical measurements. It is the quantity of electricity conveyed in one second by the current produced by an electro-motive force of one volt acting in a circuit having a resistance of one ohm, or the quantity transferred by one ampere in one second.
Farad - F
The farad is the standard unit of capacitance. Reduced to base SI units one farad is the equivalent of one second to the fourth power ampere squared per kilogram per meter squared (s4 A2/kg m2).
When the voltage across a 1 F capacitor changes at a rate of one volt per second (1 V/s) a current flow of 1 A results. A capacitance of 1 F produces 1 V of potential difference for an electric charge of one coulomb (1 C).
In common electrical and electronic circuits units of microfarads μF (1 μF = 10-6 F) and picofarads pF (1 pF = 10-12 F) are used.
Ohm - Ω
The derived SI unit of electrical resistance - the resistance between two points on a conductor when a constant potential difference of 1 volt between them produces a current of 1 ampere.
Henry - H
The Henry is the unit of inductance. Reduced to base SI units one henry is the equivalent of one kilogram meter squared per second squared per ampere squared (kg m2 s-2 A-2).
Inductance
An inductor is a passive electronic component that stores energy in the form of a magnetic field.
The standard unit of inductance is the henry abbreviated H. This is a large unit and more commonly used units are the microhenry abbreviated μH (1 μH =10-6H) and the millihenry abbreviated mH (1 mH =10-3 H). Occasionally, the nanohenry abbreviated nH (1 nH = 10-9 H) is used.
Joule - J
The unit of energy work or quantity of heat done when a force of one Newton is applied over a displacement of one meter. One joule is the equivalent ofone watt of power radiated or dissipated for one second.
In imperial units the British Thermal Unit (Btu) is used to express energy. One Btu is equivalent to approximately 1,055 joules.
Siemens - S
The unit of electrical conductance S = A / V
Watt
The watt is used to specify the rate at which electrical energy is dissipated, or the rate at which electromagnetic energy is radiated, absorbed, or dissipated.
The unit of power W or Joule/second
Weber - Wb
The unit of magnetic flux.
The flux that when linking a circuit of one turn, produces an Electro Motive Force - EMF - of 1 volt as it is reduced to zero at a uniform rate in one second.
- 1 Weber is equivalent to 108 Maxwells
Tesla - T
The unit of magnetic flux density the Tesla is equal to 1 Weber per square meter of circuit area.
Volt
The Volt - V - is the Standard International (SI) unit of electric potential or electromotive force. A potential of one volt appears across a resistance of one ohm when a current of one ampere flows through that resistance.
Reduced to SI base units,
1 (V) = 1 (kg m2 / s3 A)
4-find the voltage across the load,the figure will be provided.
5-find the equivalent capacitance,through the figure provided.
6-find the equivalent gate,gate will be made by BJT.
7-find the equivalent gate,gate will be made by Diode.
8-One multiplexer question.
9-value of charge on electron.
The electron (symbol: e−) is a subatomic particle with a negative elementary electric charge.Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure.The electron has a mass that is approximately 1/1836 that of the proton.Quantum mechanical properties of the electron include an intrinsic angular momentum (spin) of a half-integer value in units of ħ, which means that it is a fermion. Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Electrons also have properties of both particles and waves, and so can collide with other particles and can be diffracted like light. Experiments with electrons best demonstrate this duality because electrons have a tiny mass.
−1.602176565(35)×10−19 C
10-2 more question regarding the charge.
11-1 que of BJT circuit.
12-Effect of temperature on conductivity of the semiconductor.
Let’s Consider the effect of increasing the temperature on the conductivity of semiconductors.
Let's look at the factors that go into conductivity of a semiconductor and consider how each of these are affected:
sigma = ni q (me + mh)
- First let's consider q. As with conductors, as temperature increases, the charge on each carrier will not change.
- Now consider mobility. The effect of an increase in temperature on mobility is the same as it was for conductors. With the same reasoning, we see that the drift velocity will decrease causing the mobility to decrease.
- Lastly, let's consider what will happen to ni for semiconductors as temperature increases. The electrons in the valance band will gain energy and go into the higher energy levels in the conduction band where they become charge carriers! So this term will increase. Not only will it increase, but it will increase exponentially! (Promoting electrons from the valance band into the conduction band is a thermally activated process.)
- ni = C e – (E – Eave)/kT
- ni = C e – Eg/2kT
Conclusion:
The electrical conductivity of a semiconductor will increase exponentially with an increase in temperature!
sigma = C e – Eg/2kT
We can graph this equation on log vs. 1/T axes to get a linear plot (as with all Arrhenius type equations):
13-Effect of temperature on conductivity of the conductor.
How Does Temperature Affect the Conductivity of a Conductor?
Let’s Consider the effect of increasing the temperature on the conductivity of conductors.
Let's look at the factors that go into conductivity and consider how each of these are affected:
sigma = n q m
- First consider what will happen to n as temperature increases. The electrons that are charge carriers in a conductor will gain energy and go into higher energy levels. However, these energy levels are all still in the valance band. So the number of charge carriers will not change for a conductor with an increase in temperature.
- Now consider q. As temperature increases, the charge on each carrier will not change.
- Finally, what happens to the mobility? Recall that mobility is the drift velocity divided by the electric field strength. Temperature won't affect the electric field strength. But it will decrease the drift velocity because as the temperature increases, the atomic vibrations will increase, which will cause more collisions of the electrons with the crystal lattice. Hence the drift velocity will decrease.
Conclusion:
The electrical conductivity of a conductor will decrease with an increase in temperature!
The relationship is not linear, however, if we consider the resistivity, which is the reciprocal of conductivity, we do get a linear relationship:
rho = rhoroomTemp [1 + alpha(T - Troom)]
where rhoroomTemp is the room temperature resisitvity and alpha is the temperature coefficient of resistivity.The electron (symbol: e−) is a subatomic particle with a negative elementary electric charge.Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure.The electron has a mass that is approximately 1/1836 that of the proton.Quantum mechanical properties of the electron include an intrinsic angular momentum (spin) of a half-integer value in units of ħ, which means that it is a fermion. Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Electrons also have properties of both particles and waves, and so can collide with other particles and can be diffracted like light. Experiments with electrons best demonstrate this duality because electrons have a tiny mass.
−1.602176565(35)×10−19 C
14-Find the resistance of the long wire(I dont know the question exactly)
15-1 que on transformer(simple)
16-1 que on steady state
an unvarying condition in a physical process, especially as in the theory that the universe is eternal and maintained by constant creation of matter
17-1 que on majority carriers & minority carriers in BJT.
Hope this will be helpful for you & best of luck.
