Tuesday, October 11, 2011

BSNL JTO (Junior Telecom Officers) Electrical Engg. paper

When a piece of copper and another of germanium are cooled from room temperature to 800 K then the resistance of -
a) Each of them increases
b) Each of them decreases
c) Copper increases and germanium decreases
d) Copper decreases and germanium increases

When a signal of 10 mV at 75 MHz is to be measured then which of the following instrument can be used -
a) VTVM
b) Cathode ray oscilloscope
c) Moving iron voltmeter
d) Digital multimeter

When a sample of germanium and silicon having same impurity density are kept at room temperature then –
a) Both will have equal value of resistivity
b) Both will have equal value negative resistivity
c) Resistivity of germanium will be higher than that of silicon
d) Resistivity of silicon will be higher than that of germanium

When an RC driving point impedance function has zeros at s= -2 and s=-5 then the admissible poles for the function would be –
a) s = 0; s = -6
b) s = 0; s = -3
c) s = 0; s = -1
d) s = -3; s = -4

For the n-type semiconductor with n = Np and p = , the hole concentration will fall below the intrinsic value because some of the holes –
a) drop back to acceptor impurity states
b) drop to donor impurity states
c) Virtually leave the crystal
d) recombine with the electrons

The location of lighting arrestor is –
a) Near the transformer
b) Near the circuit breaker
c) Away from the transformer
d) None

Time constant of an RC circuit increases if the value of the resistance is –
a) Increased
b) Decreased
c) Neither a nor b
d) Both a and b

Telemetering is a method of –
a) Counting pulses sent over long distances
b) Transmitting pictures from one place to another
c) Transmitting information concerning a process over a distance
d) None

When the gauge factor of a strain gauge is 2, stress is 1050 kg/cm2, Y = 2.1´ 106 kg/cm2 and R is 100 ohms then the value of DR will be -
a) 2W
b) 3W
c) 4W
d) 1W

As the drain voltage is increased for a junction FET in the pinch off region then the drain current –
a) Becomes zero
b) Abruptly decreases
c) Abruptly increases
d) Remains constant

One of the following, which is not a transducer in the true sense, is –
a) Thermocouple
b) Piezoelectric pick up
c) Photo-Voltaic cell
d) LCD

When a transistor is required to match a 100W signal source with a high impedance output circuit then the connection that would be used is –
a) Common base
b) Common collector
c) Common emitter
d) Emitter follower

In a JFET gates are always –
a) forward biased
b) reverse biased
c) unbiased
d) none

The main factor which differentiate a DE MOSFET from an E only MOSFET is the absence of –
a) insulated gate
b) electrons
c) channel
d) P-N junction

An SCR conducts appreciable current when –
a) Anode and gate are both negative with respect to cathode
b) Anode and gate are both positive with respect to cathode
c) Anode is negative and gate is positive with respect to cathode
d) Gate is negative and anode is positive with respect to cathode

Silicon is not suitable for fabrication of light emitting diodes because it is -
a) An indirect band gap semiconductor
b) A direct band gap semiconductor
c) A wide band gap semiconductor
d) A narrow band gap semiconductor

An average responding rectifier type electronic ac voltmeter has its scale calibrated in terms of the rms value of a sine wave, when a square wave voltage of peak magnitude 100V is measured using this voltmeter then the reading indicated by the meter, will be –
a) 111V
b) 100V
c) 90.09V
d) 70.7V

When a four terminal T network is inserted between a source and load resistance as shown in figure then the resistance seen by the source remain the same with or without the four terminal block when R is –
a) 5W
b) 10 W
c) 15 W
d) 20 W

Which one of the following conditions for Z parameters would hold for a two port network containing linear bilateral passive circuit elements –
a) Z11 = Z22
b) Z12Z21 = Z11Z22
c) Z11Z12 = Z22Z21
d) Z12 = Z21

When the transmission parameters of the following network are A = C = 1, B = 2 and D = 3 then the value of Zin is –
a) 3W
b) 4W

While calculating Rth, constant current sources in the circuit are –
a) replaced by opens
b) replaced by ’shorts’
c) treated in parallel with other voltage sources
d) converted into equivalent voltage sources

Maxwell’s loop current method of solving electrical networks –
a) uses branch currents
b) utilizes kirchhoff’s voltage law
c) is confined to single-loop circuits
d) is a network reduction method

A transmission line of characteristic impedance Z0 = 50 ohms, phase velocity Vp = 2 x 108 m/s and length l = 1m is terminated by a load ZL= ( 30 – j 40 ) ohms. The input impedance of the line for a frequency of 100 MHz will be
a)(30 + j40 ) ohms
b)( 30 – j40 ) ohms
c)(50 + j40 ) ohms
d)(50 – j40 ) ohms

For an elliptically polarized wave incident on the interface of a dielectric at the Brewster angle then the reflected wave will be-
a) Elliptically polarized
b) Linearly polarized
c) Right circularly polarized
d) Left circularly polarized

A yagi antenna has a driven antenna-
a) Only
b) With a reflector
c) With one or more directors
d) With a reflector and one or more directors

The number of lobes on each side of a 3l resonant antenna is –
a) 3
b) 6
c) 2
d) 1

The electric field intensity of a Hertizian dipole at a remote point varies as -
Radiation resistance of a half wave folded dipole is -
a) 72 W
b) 144W
c) 288 W
d) 216W

When a carrier wave is modulated at 100% it’s power is increased by -
a)100%
b)150 %
c)50%
d)0%

On a clear sky day, the atmospheric radio noise is strongest -
a) During morning hours
b) Around mid-day
c) During nights
d) In the afternoon

TV broadcasting system in India is as per CCIR -
a) System B
b) System I
c) System M
d) System X

For the safety measurement of the internal resistance of a 25-0-25 mA meter, a laboratory multimeter whose sensitivity is equal to –
a) 1k ohm/volt can be used
b) 10 k ohm/volt can be used
c) 100 k ohm/volt can be used
d) 200 k ohm/volt can be used

In order to measure moisture in wood the most suitable method is –
a) Electrical conduction
b) Electrical – capacitive
c) Absorption of radiation
d) Equilirium- moisture vs humidity

The flow rate of electrically conducting liquid without any suspended particle cannot be measured by –
a) turbine flow meters
b) electromagnetic flow meters
c) ultrasonic flow meters
d) thermistor based heat loss flow meters

The most useful transducer for displacement sensing with excellent sensitivity, linearity and resolution is –
a) an incremental encoder
b) an abosolute encoder
c) LVDT
d) a strain gauge

When variable reluctance type tachometer has 150 teeth on the rotor & the counter records 13,500 pulses per second then the rotational speed will be–
a) 4800 rpm
b) 5400 rpm
c) 6000 rpm
d) 7200 rpm.

41. On a voltage scale, zero dB m in a 600-ohm system could refer to –
a) 1.732 V
b) 1.0 V
c) 0.7746 V
d) 0.5V

One of the following devices which is required in addition in order to measure pressure using LVDT is-
a) strain gauge
b) pitot tube
c) Bourden tube
d) Rotameter

It is required to measure temperature in the range of 13000 C to 15000 c) The most suitable thermocouple to be used as a transducer would be –
a) chromel - constantan
b) Iron - constantan
c) chromel - alumel
d) platinum- rhodium

In a CSI if frequency of output voltage is f Hz, then frequency of input voltage to CSI is-
a) f
b) 2 f
c) f/2
d) 3 f

Identify the type of chipper in the given circuit
a) Type A chopper
b) Type B chopper
c) Type C chopper
d) Type D chopper

Maximum value of charging resistance in an UJT is associated with-
a) peak point
b) valley point
c) any point between peak and valley
d) after the valley point

Thyristor A has rated gate current of 2A and thyristor B a rated gate current of 100 mA-
a) A is a GTO and B is a conventional SCR
b) B is a GTO and A is a conventional SCR
c) B may operate as a transistor
d) none of the above

In a 3 phase full converter, the output voltage during overlap is equal to-
a) zero
b) source voltage
c) source voltage minus the inductance drop
d) average value of the conducting phase voltages

Mark old the correct statement for Cycloconverters-
a) step-down Cycloconverter (CC) works on natural commutation
b) step up CC requires no forced commutation
c) load commutated CC works on line commutation
d) none of the above

In the RF amplifier stage cascade (CE-CB) amplifier is used because it gives-
a) Large voltage gain
b) Low output impedance
c) Large isolation between the input and the output
d) None of the above

Silicon diode is less suited for low voltage rectifier operation because-
a) it can withstand high temperature
b) ensures low PIV of the diodes
c) ensures lower values of capacitance in the filter
d) reduces ripple content

An amplifier of class A is that in which -
a) Base is biased to cut – off
b) Ic flows most of the time
c) Ie flows all the time
d) Vc often raises to Vcc

A transistor is in active region when-
a) IB = bIC
b) IC=bIB
c) IC=IE
d) IC=IB

For coupling purposes in RF amplifier a buffer amplifier is used because it provides-
a) Maximum loading and minimum mismatch
b) Minimum loading and minimum mismatch
c) Maximum loading and maximum mismatch
d) Minimum loading and maximum mismatch

A transistor has CE parameter as hie = 10kW, hre =20 x 10-4 , hse = 100, hoe = 25 ms. The hib for this transistor will be-
a) 100 W
b) 99.01 W
c) 5m W
d) 101kW

A FM radio receiver is tuned to a 90.6 MHz broadcast station. It will receive an image frequency of -
a) 110 MHz
b) 112 Hz
c) 114 MHz
d) 120 MHz

In the given fig RL is shorted out, then VCE will become-
a) OV
b) VCC – IBRB
c) Equal to VCC
d) None of the above

No comments:

Post a Comment

CURRENT AFFAIRS PREPARATION PLAN

“Current Affairs” and “General Knowledge” cover many topics like from economy to sports or education to politics, or even technology to automobiles. In every second some issues are happening around the world in these sectors, and to accumulate the excerpt of some highlighted news, and memorize it is a good plan to prepare current affairs and GK.

Some Important Tips to Follow:

Read Newspapers regularly

We all know that “Old is Gold”, same thing applies here too. We need to make a habit of reading newspapers regularly. I’ll suggest you to read more than one newspaper. It will be better if you read one newspaper of your mother language, and other of English. Some useful newspapers are “The Times of India”, “The Hindu”, “The Telegraph” etc. You need to start this habit at least 6 months before the actual exam that will help you to get access to all the important events of that period of time.

You need to keep an eye on what’s happening around you in your country and world as well. Trust me guys, you will surely find it interesting after several days. We all know that staying updated is always a good idea, as it will stand you apart from the rest.

Read Magazines thoroughly

This is another great option to prepare the subject we are talking about. There are many leading magazines that focus on current affairs and General Knowledge. You need to buy it from your local magazine seller, and start reading it thoroughly. These magazines beautifully categorize the articles with its genres to make it interesting to read on. Some of the useful magazines are Pratiyogita Darpan andManorma.

Try to read some business magazines and sports magazines too along with a general magazine. This will increase your chances of cracking the competitive exams with ease. Some useful business magazines areBusiness Today, Business Line etc.

Follow News Channels

You will need to follow news channels at least once a day. Now most of the leading news channels are active for 24*7. You need to pick up a suitable time for yourself to watch any favorite news channel of yours. You can watch ABP News, NDTV, Times Now, ET Now, Zee News etc. Try to go through all the breaking and highlighted news, and make it a habit.

I know that watching news channels for long will bore you, so I’ll suggest you to allocate only 30 minutes for it in a whole day. All the leading ones shows the glimpses of all important events of the day quite frequently, so 30 minutes will be enough for you to boost up your current affairs and GK knowledge.

Maintain a Diary

My teacher used to tell me that whenever you learn something try to write it down in your diary, as it will help you to memorize it in a better manner. He is so right, as this method helped me a lot to score good marks in every exam that I appeared for. As I already mentioned before that a lot of events are occurring in the country and around the world, so it is easily understandable that it is not easy to remember everything. It’s always a superb idea to maintain a diary of current events.

You need to update this diary on a daily basis with all the events that you consider as important ones. This diary will become quite useful for the revision part, as it will provide you information about all the important events at a place. You should keep revising the diary frequently, as it will help you to memorize important names, dates, awards etc.

Channelize your Preparation Accordingly

All the competitive exams are not same, as all of them have different pattern, even when it comes to the same topic as ‘Current Affairs’ or ‘GK’. For example for civil services exam, you need to give importance on events of National value. On the other scenario, in matter of bank job exam, the focus should be on the news on banking sectors, and economic and business news.

Thus I’ll suggest you to prepare as per the exams you are appearing for, as channelizing your preparation according to the pattern of the exam will accelerate your chance of getting selected.

Use Internet Resources

Google, YouTube and Wikipedia are my favorite teachers’; one of my friends told me this once. This is quite true indeed, so you should use all the available online resources to study current affairs and GK for exams. For example this blog is all about “Current Affairs”, so you can check this blog regularly by subscribing to us (check the sidebar for subscription options). You can actively take part some forums that are focusing on current events. The good part is you can follow the websites of all leadingnewspapers online if you don’t have enough time to read newspapers.

Use Social Networking Sites for Good

Believe me or not you can surely use social networking sites to your benefits. Especially to prepare current affairs and General knowledge Facebook, Twitter, LinkedIn and StumbleUpon may help you a lot. You can join some Facebook pages, or follow some twitter accounts that are related to current affairs. You can join our Facebook Page too for this matter, or connect with me at LinkedIn or circle me in Google Plus for all the information on recent happenings to boost up your General Knowledgeability.

Give Priority to your Strength

We usually find difficulties when we try to learn everything at once. In that process basically we study a lot, but remember a little. We need to first select our strength areas for our preparation. Try to givepriority to your strength areas. It may be Sports, economy, Government Affairs or technology. Suppose you are applying for Bank exams, then you should prepare industry related news. Along with that you may pick any 2-3 areas of your strength like sports or technology. You need to prepare these sections to the utmost level. I can assure you that these strategies will help you to score much better in Current Affairs section.

Participate in Online Quizzes

You should participate in some free quizzes that are available online to evaluate yourself. For this matter you can easily access our “Quiz Section”. This will give you proper idea whether you are ready for the big exam day or not. As an added factor it will also provide you confidence i.e. very much essential. You can download Monthly-wise current affairs questions from Here.