EKT Question of MECHANICAL ENGINEERING

PART B-1 AE (M): MECHANICAL ENGINEERING
1. An impulse turbine
(A) Makes use of a draft tube
(B) Always operates submerged
(C) Converts the pressure head into velocity
head through the vanes
(D) Is most suited for low head installations
2. Power required to drive a centrifugal
pump is directly proportional to
(A) Diameter of its impeller
(B) Square of diameter of its impeller
(C) Cube of diameter of its impeller
(D) Fourth power of diameter of its
impeller
3. The locus of the common point on the
two meshing spur gears is known as
(A) Addendum circle
(B) Duodenum circle
(C) Pitch circle
(D) Base circle
4. When there is a reduction in amplitude
over every cycle of vibration then the body
is said to have
(A) Free vibration
(B) Forced vibration
(C) Damped vibration
(D) Natural vibration
5. For machining at high speed the tool
material should have
(A) Wear resistance
(B) Red hardness
(C) Toughness
(D) All of these
6. MIG welding is
(A) A gas welding process
(B) An electric resistance welding process
(C) A electric resistance welding process
(D) A forge welding process involving high
temperatures and low pressures
7. The ability of sand to permit the metal to
shrink when it solidifies is known is
(A) Plasticity (B) Permeability
(C) Collapsibility (D) Cohesiveness
8. Rivets are generally specified by
(A) Overall length
(B) Shank diameter
(C) Thickness of plates to be jointed
(D) Diameter of head
9. Which of the following is steady flow
compressor
(A) Reciprocating compressor
(B) Centrifugal compressor
(C) Voot blower
(D) Vane blower
10. A closed cycle gas turbine works on
(A) Carnot cycle (B) Rankine cycle
(C) Brayton cycle (D) Joule cycle
11. Thermal conductivity of solid metals
(A) Decreases with rise in temperature
(B) Does not vary with temperature
(C) Increases with rise in temperature
(D) Remains constant with rise in
temperature
12. During adiabatic saturation process, air
property which remains constant, is known
as
(A) Wet bulb temperature
(B) Dry bulb temperature
(C) Relative humidity
(D) Specific humidity
13. Bell-Coleman cycle as applied to
refrigeration operates
(A) On open air system
(B) On vapour compression system
(C) On vapour absorption system
(D) On none of these
14. The gears in which axes of the shaft
connected by them, intersect, are known as
(A) Spur gears (B) Bevel gears
(C) Spiral gears (D) Gear train
15. Shot peening
(A) Is done at re-crystallization temperature
(B) Changes the crystalline structure at
materials
(C) Improves the fatigue life of small parts
(D) Refines the grain structure
16. In a bomb calorimeter the heat released
by the fuel is absorbed by
(A) Atmospheric air
(B) Water
(C) Metal container
(D) Bomb, water and metal container
17. Nitriding is done
(A) On low carbon steels only
(B) To impart blue colour to steels
(C) To improve machinability
(D) To increase surface hardness
18. The extent of cold work that a metal can
withstand depends on
(A) Purity of metal
(B) Carbon percentage
(C) Ductility
(D) Room temperature
19. Which engine has the highest air fuel
ratio
(A) Petrol engine (B) Gas engine
(C) Diesel engine (D) Gas turbine
20. Annealing of steels is done to
(A) Remove internal stresses
(B) Produce soft core under hard surface
(C) Produce hard core under soft surface
(D) Introduce capacity to withstand shocks

EKT Question of ELECTRONICS AND COMMUNICATIONS

The model question paper only offers a broad overview and does not purport to represent either
the syllabus or the pattern of questions that would appear in the Engineering Knowledge Test
PART B-4 AE (L): ELECTRONICS AND COMMUNICATIONS
1. In a communication system, noise is
most likely to get into the system
(A) at the transmitter
(B) in the channel
(C) in the information source
(D) at the destination
2. When modulation frequency is doubled,
the modulation index is halved, and the
modulating voltage remains constant, the
modulation system is
(A) amplitude modulation
(B) phase modulation
(C) frequency modulation
(D) angle modulation
3. Impedance inversion may be obtained
with
(A) a short – circuited stub
(B) an open – circuited stub
(C) a quarter – wave line
(D) a half – wave line
4. HIGH frequency waves are
(A) observed by the F2 layer
(B) reflected by D layer
(C) capable of use for long-distance
communication on the moon
(D) affected by the solar cycle
5. Which one of the following terms does
not apply to the Yagi-uda array
(A) Good band width
(B) Parasitic elements
(C) Folded diploe
(D) High gain
6. A duplexer is used
(A) to couple two different antennae to a
transmitter without mutual interference
(B) to allow one antenna to be used for
reception or transmission without mutual
interference
(C) to prevent interference between two
antennae when they are connected to
receiver
(D) to increase the speed of the pulses in
pulsed radar
7. Indicate which of the following system is
digital
(A) Pulse – Position modulation
(B) Pulse – Code modulation
(C) Pulse – Width modulation
(D) Pulse – Frequency modulation
8. A forward error correcting code corrects
errors only
(A) requiring partial retransmission of the
signal
(B) requiring retransmission of entire signal
(C) using parity to correct to errors in all
cases
(D) requiring no part of the signal to be
transmitted
9. A typical signal strength received from a
geosynchronous communication satellite is
of the order of
(A) a few milli watts
(B) kilo watts (C) watts
(D) few pico watts
10. Telephone traffic is measured
(A) with echo cancellers
(B) by the relative congestion
(C) in terms of the grade of service
(D) in erlangs
11. Positive logic in a logic circuit is one in
which
(A) logic 0 and 1 are represented by 0 and
positive voltage respectively
(B) logic 0 and 1 are represented by
negative and positive voltages respectively
(C) logic 0 voltage level in higher than
logic 1 voltage level
(D) logic 0 voltage level is lower than logic
1 voltage level
12. A half-adder can be made from
(A) two NAND gates
(B) a NOT gate and an OR gate
(C) an AND gate and an OR gate
(D) an AND gate and an X-OR gate
13. Which of the following devices has its
characteristics very close to that of an ideal
current source.
(A) Field effect transistor
(B) Transistor in common bas mode
(C) Zener diode
(D) MOSFET
14. The main use of a common base
transistor amplifier is
(A) as voltage amplifier
(B) current amplifier
(C) for matching a high source impedance
to a low load impedance
(D) for rectification of a.c. signal
15. A class-B amplifier is biased
(A) Just at cut-off
(B) nearly twice cut-off
(C) at mid point of load line
(D) so that IB equals jut IC
16. If the peak transmitted power in a radar
system is increased by a factor of 16, the
maximum range will be increased by a
factor of
(A) 2 (B) 4 (C) 8 (D) 16
17. A high PRF will (indicate the false
statement)
(A) make the returned echoes easier to
distinguish from noise
(B) make target tracking easier with conical
scanning
(C) increase the maximum range
(D) have no effect of the range resolution
18. A solution to the “blind speed” problem
in a radar system is to
(A) change the Doppler frequency
(B) vary the PRF
(C) use mono pulse
(D) use MTI
19. The number of active picture elements
in a television image depends on
(A) fly back time
(B) CRT screen size
(C) received band width
(D) FB ratio of receiver antenna
20. In a colour TV, the three primary
colours are
(A) red, orange and blue
(B) red, blue and green
(C) red, green and yellow
(D) red, orange and green

WBUT question of Analog communication 2007

2007
ANALOG COMMUNICATION
GROUP-B
2 (A) Define amplitude modulation and modulation index. Use a sketch of sinusoidally modulated AM waveform to help to explain the definition.
(b) Derive the expression between the output power of an AM transmitter and the depth of modulation.
3. What is angle modulation ? Justify that frequency modulation is an angle modulation.
4. drive the expression of single to noise ratio of DSB-SC system.
5.(A)What do you mean by FDM? when it is used?
(b) What is Carson's rile?
6. The equation for an FM wave is
S(t)=10sin(5.7×108t + 5sin12×103t)
Calculate:
(a) carrier frequency
(b) modulating frquency
(c) frequency deviation
(d) modulation index
(e) power dissipated in 100 ohm
GROUP-C
7.(a) What is the concept behind NBFM ? Drive its equation.
(b) Explain how FM can be generated using VCO.
(c) Discuss about the roles of pre-emphasis and de-emphasis circuit in FM
broadcasting.
8.(a) Draw the block diagram for generation and detection of PCM system.
(b) What is quantization? Find signal to quantization noise ratio for PCM system.
(c) A signal is sampled at Nyquist rate of 8 kHz and is quantized using 8 bit uniform quantizer. Assuming SNRq for a sinusoidal signal, calculate bit rate, SNRq and BW.
9 (a) State and prove parseval's power theorem.
(b) Describe with a block diagram the principle of operation of a square low modulator generating DSB-SC.
(c) Explain the advantages and disadvantages of modulation.
10 (a) Draw the block diagram of a superheterodyne receiver and explain its working principle .
(b) Explain the operation of balanced modulator.
11 Write short notes on any three of the following :
(a) Entropy and its properties
(b) QCM
(c) termal noise
(d) power spectral density function
(e) pulse coded modulation