Saturday, 28 May 2016

Data Structure/Level-1/Paper-01


1. When new data are to be inserted into a data structure, but there is not available space; this situation is usually called ….
A. Underflow
B. overflow
C. houseful
D. saturated

Ans:  B. overflow

2 . Which is/are the application(s) of stack
A) Function calls
B) Large number Arithmetic
C) Evaluation of arithmetic expressions
D) All of the above

Ans: D) All of the above

3. which of the following data structure is non linear type?
A) String
B)Lists
C) Stacks
D) Graph

Ans: D) Graph

4.which of the following data structure is linear type?

A) Graph
B) Trees
C) Binary Tree
D) Stack
Ans: D) Stack

5. Which of the data structure can't store the non-homogeneous data elements?

A) array 
B) Records
C) Pointers
D) Stacks 
Ans: A) array 



__________________________Points to remember______________________________




Types of Data structures:


There are two types of data structure
i) Linear  (Stack,liked list,queue )
ii) Nonlinear  (eg. Graph, Tree)

The more commonly used data structures include lists,arrays,stacks ,queues,heaps, trees and graph.

Arrays:

The simple type of data structure is linear array. A linear array  is list of a finite number of n of similar data elements .

Linked list:
A list is an ordered structure of data.It is often used to store objects that are to be processed sequentially . A list can be used to create a queue.


 Stack:
A stack is a last in, first out (LIFO) data structure. Items are removed from a stack in the reverse order from the way they were inserted

                There are two stack errors that can occur:
                                     Underflow: trying to pop  an empty stack
                                      Overflow: trying to push onto an already full stack
 Queue:
A queue is a first in, first out (FIFO) data structure. This is accomplished by inserting at one end (the rear) and deleting from the other (the front).Items are removed from a queue in the same order as they were inserted.The process to add an element into queue is called Enqueue and the process of removal of an element from queue is called Dequeue.

 Deque 
 A deque is a double-ended queue. Items can be inserted and removed at either end. Deques (pronounced deck) are not heavily usedDeque" is not to be confused with dequeueing ( a queue operation)

Trees:
Data frequently contain a hierarchical relationships between various elements . The data structure which reflects this relationships is called a rooted tree graph or a tree.


Graph 
Graphs are data structures rather like trees. Graphs often have a shape dictated by a physical or abstract problem . For example , nodes in  a graph may represent cities , while edges may represent airline flight routes between the cities . Nodes are traditionally called vertices


Wednesday, 25 May 2016

CONTENTS


BROAD BAND :

Small Form-factor Pluggable (SFP) Optical Transceivers

Broad Band Equipment

DSL Technology (MCQs)

IP address Basic concepts in networking 



BASIC ELECTRICAL

Basic Electrical/Electric Current/Level-0/Paper-01

Basic Electrical/Resistance/Level-1/Paper-02

Basic Electrical/Electrical circuits/Level-0/Paper-04

Basic Electrical/Network theorems/Set-1/Paper-02

Basic Electrical/Capacitance/Set-1/Paper-03 

Basic Electrical/Inductance/Level-0/Paper-01





COMPUTER SCIENCE

CS/Computer Generation/Level -0/Paper-01



ELECTRONICS ENGINEERING :




GENERAL SCIENCE:












GS & EL/X-rays/Level-0/Paper-01


Properties of X-ray

1. X rays are electromagnetic(EM) waves of very short wave length

2. They travel in straight lines with the velocity of light

3.They are invisible to eyes

4. Under suitable conditions , X-rays are reflected & refracted like ordinary light

5. They are not deflected by electric and magnetic fields.

Wave length=1Å

X-rays can penitrate throughbthe substances which are opaque to ordinary light eg: wood,flesh,thick paper,thin sheets of metals

6)They cause Fluorescence on many substanstances like barium,cadmium, tungstate, Zinc,sulphate etc.

7)X-rays can ionise a gas through which they pass

8) when X-rays are fall on certain metals ,they liberate photo electrons(photo electric effect)

9)when X-rays fall on heavy metals ,they produce secondary X-rays

10)X-rays have destructive effects on living tissues
(When they are exposed to human body , they cause reddening of the skin,sores and serious injuries to the tissues and gland .they can destroy white corpuscles of the blood)


Basic Electrical/Resistance/Level-1/Paper-02


Resistance is defined as the property of a substance due to which it opposes  the flow of electricity  through it.Unit ohm  Ω.


Laws of Resistance


(i) Resistance decreases with decrease in   its length, l.

(ii) Resistance decreases with increase in the cross-section A of the conductor.
     i.e. Thicker wire has   lower resistance.

(iii) Resistance depends on the nature of the material the conductor made of.

(iv) Resistance also depends on the temperature of the conductor.

 
          
where ρ is a constant depending on the nature of the material of the conductor and is known as                   its specific resistance or resistivity.Unit ohm-metre(Ω-m).

Conductance :

Conductance (G) is reciprocal of resistance.Unit  siemens (S).
 Earlier, this unit was called mho.

          

 Conductivity :



σ is called the conductivity or specific conductance of a conductor.


It is seen from the above equation that the conductivity of a material is given by

Hence, the unit of conductivity is siemens/metre (S/m).


Effect of Temperature on Resistance


  • Insulators (such as paper, rubber, glass, mica etc.) are said to possess a negative temperature-coefficient of resistance 
  • Semiconductors have a positive temperature co-efficient of resistance.
  • Metals have a positive temperature co-efficient of resistance.
  •  The effect of rise in temperature is to decrease the resistance of electrolytes,and partial conductors such as carbon.

Q1. A given wire is stretched to double its length. How much its resistance change ?

(1) resistance is same
(2) resistance becomes four times
(3) resistance becomes two times
(4) resistance becomes half times

Ans: 2
Hint:

After stretching the resistance changes but resistivity remains the same.
As volume of wire is constant so area and length are inversely proportional.


So if the length is doubled by stretching , area of cross section becomes halved.
After stretching wire length is doubled.New length is 2l .


.
Q2. Two cylindrical resistors, R1 and R2, are made of identical material. R2 has twice the length of R1 but half the radius of R1.

Solution:
The area of a circle is equal to the square of its radius times Pi.Relationship between the cross section  area of half the radius of R1 with R2.




Resistance is inversely proportional to the area of cross section.






EL Engg/Semiconductor Engineering/Level-1//Paper-01


1. In intrinsic semiconductors, number of electrons __________ number of holes. 
(a) Equal (b) Greater than (c) Less than (d) Can not define

Ans: (c) Less than



2. Fermi energy level for intrinsic semiconductors lies

(a) At middle of the band gap (b) Close to conduction band
(c) Close to valence band (d) None

Ans:(c) Close to valence band

3. Flow of electrons is affected by the following


(a) Thermal vibrations (b) Impurity atoms (c) Crystal defects (d) all

Ans: (d) all



4. Fermi level for extrinsic semiconductor depends on 
(a) Donor element (b) Impurity concentration (c) Temperature (d) All

Ans:(d) All



5. Fermi energy level for n-type extrinsic semiconductors lies 
(a) At middle of the band gap (b) Close to conduction band 
(c) Close to valence band (d) None

Ans: (b) Close to conduction band 





_______________________________SOLUTION___________________________________

5. Ans: (b) Close to conduction band.
The Fermi level lies in the middle of the forbidden gap.
Fermi level lies near valence band in P type and near conduction band in N type







Tuesday, 24 May 2016

General Science/Level-1/Set-1/Paper-01

1. Radiations infra-red region may be detected with the help of
a)barometer
b)bolometer
c)spectrometer
d)sonometer
Ans:B bolometer

2. Simple astronomical telescope consist of two
A)convex lenses
B)concave lenses
C)one convex lens and other concave lens
D)Plano convex lenses
Ans: a convex lensses

3.A yellow object when seen through a red glass appears as
A)yellow
B)red
C)white
D)black
Ans.d black

4.X rays are emitted when
A)high energy electrons hit a substance of low molecular weight
B)high energy electrons hit a substance of high molecular weight
C)low energy electons hit any substance
D)low energy electons hit a substance of high molecular weight
Ans:b

5. Which of the following can be deflected by a magnet?
A)radio waves
B)X rays
C)beta rays
D)ultra violet rays
Ans.B beta rays

Wednesday, 11 May 2016

EL/Power Amplifiers/Level-1/Set -1/Paper-01

1.Which of the push-pull amplifiers is presently the most popular form of the class B power amplifier?

A) Quasi-complementary
B)Transformer-coupled
C)Complementary-symmetry
D)None of the above
 Ans:A) Quasi-complementary

2. In a class C amplifier 
A) Efficiency and distortion both are maximum 
B) Efficiency and distortion both are minimum. 
C) Efficiency maximum but distortion minimum. 
D) Efficiency minimum but distortion maximum

3. High power efficiency of the push-pull amplifier is due to the fact 

A) Each transistor conducts on different cycles of the input. 
B) Transistors are placed in CE configuration. 
C) There is almost no quiescent collector current 
D) Low forward biasing voltage is required.

4. Which amplifier is commonly used as a frequency multiplier?
A) class A
B) class B
C) class C
D) all of the above

Ans:D) all of the above