Rearrange the following letters so as to form one word:
NEW DOOR
Answer : ONE WORD
...
Monday, January 26, 2015
Sunday, January 25, 2015
ohms law and its limitations
At constant temperature the current flowing through a conductor is directly proportional to voltage and inversly proportional to resistance.
...
A domestic mixer uses the __________ motor
A domestic mixer uses the __________ motor
(A) induction motor(B) reluctance motor(C) universal motor(D) permanent magnet synchronous motor
Answer : universal motor
...
What is the difference between Electrical and Electronics ?
What is the difference between Electrical and Electronics ?
Electrical --- study of current flow in conductors.
Electronics ---study of current flow in semiconducto...
A boy and a doctor was fishing.The boy is the doctor's son but the doctor is not the boy's father.who is the doctor?
A boy and a doctor was fishing.The boy is the doctor's son but the doctor is not the boy's father.who is the doctor?
Answer : Doctor is boy's mothe...
Thursday, January 22, 2015
If the no of valence electrons in an atom is less than four, then it is referred as .......................
If the no of valence electrons in an atom is less than four, then it is referred as .......................
a. semiconductor
b. conductor
c. insulator
Answer:
valence electron < 4 - conductor
valence electron > 4 - insulator
valence electron = 4 - semiconductor&nbs...
Wednesday, January 21, 2015
What happens when a d.c motor is connected across an ac supply?
What happens when a d.c motor is connected across an ac supply?
Since on ac supply, reactance will come in to play,the a.c supply will be offered impedance(not resistance) by the armature winding.consequently,with a.c supply,current will be much less.The motor will run but it would not carry the same load as it would on d.c. supply.
There would be more sparking at the brushes
Though motor armature is laminated as a rule, the field poles are not. consequently,eddy currents will cause the motor to heat up eventually burn on a.c. supply....
Monday, January 19, 2015
Why transformers are rated in KVA and motors are rated in KW ?
The power factor of transformer is dependent on load we only
define Volt-ampere rating and does not include power factor but in case of motors,
power factor depend on construction and hence rating of motors is in
KW and include power facto...
Sunday, January 18, 2015
Why we can’t store AC in Batteries instead of DC?
Why we can’t store AC in Batteries instead of DC?
We cannot store AC in batteries because AC changes their polarity upto 50 (When frequency = 50 Hz) or 60 (When frequency = 60 Hz) times in a second. Therefore the battery terminals keep changing Positive (+ve) becomes Negative (-Ve) and vice versa, but the battery cannot change their terminals with the same speed so that’s why we can’t store AC in Batteries.
Also when we connect...
Saturday, January 17, 2015
Which of the following equations is valid for a 3-phase 4-wire balanced star-connected load?
Which of the following equations is valid for a 3-phase 4-wire balanced star-connected load?
(a) IR + IY + IR = IN = O
(b) IN + IY – IB = IN
(c) IR – IY + IB = IN
(d) VB + VR + VY ⁄ Z =N
Answer: IR + IY + IR = IN = O
Balanced circuit means the magnitude of each phase current is equal and neutral current is zer...
Does zero watts bulb consume no power ?
There is no bulb which consumes zero watt, it is not possible to light a bulb without drawing an current and consuming greater than zero watts .
Actually a zero watt bulb consumes about 12 to 15 watts, the inaccurate electric meters of the early days could not measure such a negligible amount of consumption as during those days,the energy meter had a rotating disc and when all other lights switched off,the disc would have minimum rotation,which...
The number of protons in silicon and germanium atom is
The number of protons in silicon and germanium atom is
a) 4 ,32b) 16,32c) 28,14d) 14,32
Answer : 14,32...
According to KVL, the algebriac sum of all IR drops and emf is in any closed loop of a network is always
According to KVL, the algebriac sum of all IR drops and emf is in any closed loop of a network is always
a. zero
b. postive
c. negative
d. determined by battery emfs.
Answer: The algebraic sum of voltage drops and emfs in a closed circuit is equal to zero.
...
Friday, January 16, 2015
What is hunting ?
What is hunting ?
The oscillations of rotor due to sudden application or removal of load is called swinging or hunting.
During hunting there are changes the current drawn by the motor which may cause problem to other appliances connected to the same line.Hence hunting is not desirable phenomenon from motor point of view and must be prevented.
...
What are the disadvantages of low power factor?
What are the disadvantages of low power factor?
Low power factor increases the current drawn from the supply to supply same power to the load.The high current due to low p.f has the following disadvantages:
Large conductor size and results in high cost
More copper losses and poor efficiency.
Large voltage drop,results in poor regulation....
Thursday, January 15, 2015
EEE symposium-Ampere2k15-selvam college of technology
College : selvam college of technology
Event Name : ampere2k15
Department : EEE
Event Type : Symposium
Email id : ampere2k15@gmail.com
Event Description :
Technical Events
1.Paper Presentation
2.Project Presentation
3.Circuit...
REMOTE CONTROL FOR HOME APPLIANCES
connect this circuit to any of your home appliances (lamp, fan, radio, etc) to make the appliance turn on/off from a TV, VCD or DVD remote control. The circuit can be activated from up to 10 metres.
...
The period of a sine wave is 1/50 seconds. its frequency is
The period of a sine wave is 1/50 seconds. its frequency is
A. 20 HZ
B. 30 HZ
C. 40 HZ
D. 50 HZ
Answer: 50 HZ
F = 1/T = 50 ...
A DC chopper remains ON for 36 μs. and OFF for 12 μs.What is its duty cycle ?
A DC chopper remains ON for 36 μs. and OFF for 12 μs.What is its duty cycle ?
A. 0.25
B. 0.75
C. 0.5
Answer: 0.75
Ton = 36 μs.
Toff = 12 μs.
T = Ton + Toff = 48 μs.
Duty cycle = Ton / T
= 36 / 48
= 0....
Wednesday, January 14, 2015
If the supply frequency increases, then skin effect is ...........
Answer: increases
The skin effect depends upon the following factors:
Nature of material
Diameter of wire - increases with the diameter of wire
Frequency - increases with the increases in frequency.
Shape of wire - less for stranded conductor than the solid conductor.
Skin effect is negligible for Frequency < 50 Hz
Conductor diameter < 1 C...
ANNA UNIVERSITY EXAMINATION RULES
Sl.
No.
Nature of Malpractice
Maximum Punishment
1
Appeal by the candidate in the answer script o
show mercy by way of awarding more than
deserving marks.
Fine of Rs. 100/- per subject.
2
The candidate writing his/her name in the
answer script.
3
The candidate writing his/her registration
number/college name in places other than
specified in the answer script.
4
Any special marking in the answer script by the
candidate.
5
The candidate communicating with
neighbouring...
Tuesday, January 13, 2015
How does a bird does not get electric shock when they sit on electric wire?
How does a bird does not get electric shock when they sit on electric wire?There is no voltage difference along a single wire the birds sitting on.since the birds are touching only one wire,the circuit is incomplete and the birds are safe.
To get shocked,electricity has to travel through its body;this requires two conductors.
Large birds can be shocked because they can make contact with two conductors,usually at a metal power pole...
What is the difference between unilateral and bilateral elements?
What is the difference between unilateral and bilateral elements?
Bilateral element: Voltage-current relation is the same for current flowing in either direction.
example: resistor,inductor and capacitor.
Unilateral element: different relations between Voltage and current for the two possible directions of current.
example: Vacuum tubes, silicon diodes, metal rectifiers ec...
Anna university BE/ B.TECH FINAL YEAR Project report format
Anna university BE/ B.TECH FINAL YEAR Project report format
Final year students of the Anna university should follow the following format to do the project report works.
To download: CLICK HER...
Which word, if pronounced right, is wrong, but if pronounced wrong is right?
Answer: the word 'Wrong'
...
Monday, January 12, 2015
In a SCRs
In a SCRs
(a) Both Latching current and holding current are associated with turn-off process
(b) Latching current is associated with turn-off process and holding current with turn on process
(c) Holding current is associated with turn-off process and Latching current with turn-on process
(d) Both Latching current and holding current are associated with turn on process
Answer: (c) Holding current is associated with turn-off process and Latching current with turn-on proce...
civil service interview question
A fresher was sitting in an interview. The interviewer said, "This is the last question of your interview. Tell me the accurate position of the center of this table where your resume is kept."
How can he answer this question? What will you have answered to such a question?
answer:
Put your finger confidently at a supposedly center point of the table and tell him that this is the exact center point.
The interviewer will ask, “How do you know...
The electric motor used in portable drills is.............
The electric motor used in portable drills is.............
a.capacitor-run motor
b.hysteresis motor
c. universal motor
d. repulsion motor
Answer: universal mot...
A and B are young ones of C. If C is the father of A but B is not the son of C. How are B and C related
A and B are young ones of C. If C is the father of A but B is not the son of C. How are B and C related
a. Niece and Uncle
b. Daughter and Father
c. Niece and Uncle
d. Daughter and Mother
Answer: b
C has two children A and B, if A is his son, B must be his daughter. ...
Sunday, January 11, 2015
What is the difference between active and passive elements ?
What is the difference between active and passive elements ?
An active element is one, which is capable of generating the energy on its own. Examples,transistor,current source , FET, ect.
A passive element is one, which is incapable of generating energy on its own. But it is capable of storing and dissipating energy.It always need some external source of power.Examples, resistor, capacitor, inductor, ec...
The quantity of charge that will be transferred by a current flow of 10 A over 1 hour period is
The quantity of charge that will be transferred by a current flow of 10 A over 1 hour period is
a. 10 C
b. 36000 C
c. 2400 C
d. 160 C
Answer:
t= 1 hr = 3600 sec
Q=I*t = 10*1*3600 = 36000 coulom...
Saturday, January 10, 2015
Why power factor is not more than unity?
Power factor is the cosine angle between voltage and current.The magnitute of cosine is never greater than one.
The power factor is equal to watts/ Volt-Amps.Watts can never exceed Volt-amps
...
A lamp draws 0.5 A at 230 V. If the voltage is reduced to 115 V, will the current be halved ?
A lamp draws 0.5 A at
230 V. If the voltage is reduced to 115 V, will the current be halved ?
No.because ohms law is true for constantant temperature.If
the voltage is reduced from 230 to 115 volt,results in decrease in resistance. Consequently
ohms law cannot be applied...
Friday, January 9, 2015
Why field rheostat is kept in minimum position while armature rheostat is at maximum position ?
Why field rheostat is kept in minimum position while armature rheostat is at maximum position ?
At the time of starting of motor, the armature resistance is kept at maximum position to control and reduce the high starting current and field rheostat at minimum position to ensure that speed does not go beyond rated value and to have high starting torqu...
Thursday, January 8, 2015
A 230 V supply is connected across series combination of two bulbs of 60W and 100W respectively.which bulb will glow bright and why ?
A 230 V supply is connected across series combination of two bulbs of 60W and 100W respectively.which bulb will glow bright and why ?
we know in series connection the current is same and voltage is different which depends on resistance of the individual elements connected.
P=V^2/ R, to maintain this relationship the resistance of 60W bulb is greater and voltage across 60 W bulb is more(V=IR).so 60W bulb will glow brighter than 100W bul...
Wednesday, January 7, 2015
What is the difference between active and passive elements ?
An active element is one, which is capable of generating the energy on its own. Examples,transistor,current source , FET, ect.
A passive element is one, which is incapable of generating energy on its own. But it is capable of storing and dissipating energy.It always need some external source of power.Examples, resistor, capacitor, inductor, ec...
Permanent magnet moving coil instrument can be used for ..........
Permanent magnet moving coil instrument can be used for ..........
a. ac work only
b. dc work only
c. both dc and ac work
d. none of the above.
Answer: dc work only
In a.c, the deflecting torque of the instrument reverses if the current reverses and hence the pointer cannot follow the rapid reversals and the deflection corresponds to a mean torque value of zero.so these instruments cannot be used for a.c....
In a.c system, we generate sine waveform because....................
In a.c system, we generate sine waveform because....................
a. it can be easily drawn.
b. it produces least distrubance in electrical circuits.
c.it is nature standard.
d.other waves cannot be produced easily.
Answer:it produces least distrubance in electrical circuit...
Tuesday, January 6, 2015
Why is a shunt motor called constant speed motor ?
Why is a shunt motor called constant speed motor ?
In dc shunt motor flux produced by field winding is proportional to field current Ish. Here the input voltage is constant so field current and flux is also constant.Therefore, dc shunt motor is also called a constant flux or constant speed moto...
Saturday, January 3, 2015
What do you mean by balanced load and un balanced load ?
A load is said to be balanced load, if power factors and phase currents in the 3-phases are equal.
A load is said to be ubalanced load, if power factors and phase currents in the 3-phases are unequal.
...
What is the relation between electrical and mechanical degree?
The relationship between mechanical and electrical degrees is
1 degree mechanical = (P/2) electrical degrees
Where P = no. of poles
i.e. for 1 deg of mechanical revolution of conductor inside a magnetic field produces (P/2) degree electrical outpu...
How the direction of rotation of a dc motor can be reversed ?
The direction of a dc motor can be reversed either by reversing current through field winding or armature winding . Usually current through armature will be reversed.
...
Friday, January 2, 2015
Define power factor.
The power factor is the cosine of the angle between voltage and current.
Power factor = resistance / impedance
( or)
Power factor = real power / apparent power
...
Define analog signal & digital signal.
The amplitude of the signal varies continously with time.This signal is called analog signal.
A signal defined at discrete instants of time is called digital signal....
Mention the applications of PN diode ?
As switches
As rectifiers
Power supplies
Clippers & Clampers
Digital systems
Communication systems
...
