FEEE VIVA Q & A : Diploma karnataka

BEEE LAB VIVA QUESTIONS

SI Unit of resistance is ohm
SI unit of charge is coulomb
SI Unit of current is ampere
Unit of voltage is volt
Unit of power is watt
Unit of electrical energy is watt hour or unit
Instrument used to measure current is ammeter
Instrument used to measure voltage is voltmeter
Instrument used to measure power in wattmeter
Instrument used to measure electrical energy is energy meter
Instrument used to measure resistance is ohm meter
The property of the material which opposes the flow of electric current is resistance
The flow of electron in a circuit is called current
The potential difference between any two points in a circuit is called voltage
The product of current and resistance is called voltage
The product of current and voltage is called power
Rate of electrical work done is called power
Total amount of electrical work done is electrical energy
Resistance is directly proportional to the length of the conductor
Resistance is inversely proportional to area of cross section of the material
The material which does not allow current to flow through it is called insulator
The material which allows current to flow through it is called conductor
The material whose conductivity is in between conductor and insulator
When two resistance r₁ and r₂ are in series then the equivalent resistance is r_eq= r₁₊ r₂
When two resistance r₁ and r₂ are in parallel then the equivalent resistance is 1/r_eq= 1/r₁₊ 1/r₂
Unit of magnetic flux is Weber
Total number of magnetic field lines in a magnetic field is called magnetic flux
The ratio of flux by area is called magnetic field
Opposition to the flow of flux is called reluctance
Unit of self inductance is Henry
Unit of capacitance is farad
Motor converts electrical energy to mechanical energy
Generator converts mechanical energy to electrical energy
Frequency of AC in India is 50Hz
In pure resistive circuit current is in phase with voltage
In pure capacitive circuit current leads the voltage by 90 degree
In pure inductive circuit current lags voltage by 90 degree
Inductive reactance is given by X_l=ωL
Capacitive reactance is given by X_c=1/ωC
Cosine of the phase angle between current and voltage is called power factor
Power factor in a circuit is improved by connecting capacitor in the circuit
Voltage in three phase AC supply is 440 V
In three phase system voltages are displaced by 120 degree
Transformer works on the principle of mutual induction
DC generator works on the principle of dynamically induced emf
Electric choke is an example for self induced emf
Lenz law is used to find the polarity of induced emf
Starters are required to limit the heavy starting current
MCB means master circuit breaker
Fuse is connected in series with the appliance to protect it from heavy current
Fuse wire is made of lead-tin alloy
HRC fuse means high rupturing capacity fuse
SPDT means Single pole double throw switch
SPST means Single pole single throw switch
DPDT means Double pole double throw switch
TPST means triple pole single throw switch
ELCB is used to prevent earth leakage current
Earthing brings the electrical equipment to zero potential
In earthing GI wire is used to connect the equipment to earth
Cell converts chemical energy to electrical energy
Battery is a group of cells
In lead acid battery anode is made of lead peroxide
In lead acid battery cathode is made of lead
In lead acid battery electrolyte is sulphuric acid
In fully charged lead acid battery voltage is 2.7V
In discharged lead acid battery voltage is 1.8V
Intrinsic semiconductor are pure semiconductors
Silicon and germanium are pure semiconductors
Examples of Pentavalent impurities: arsenic bismuth phosphorus
Examples of trivalent impurities are :gallium indium boron
Process of adding an impurity is called doping
When Pentavalent impurity is added to pure semiconductor n type semiconductors are formed
When Trivalent impurity is added to pure semiconductor p type semiconductors are formed
In n type electrons are the majority carriers
In p type holes are the majority carriers
In n type holes are minority carriers
In p type electrons are minority carriers
Barrier potential of silicon diode is 0.7 V
Barrier potential of germanium diode is 0.3 V
Diode is a unidirectional device
Rectifier converts AC voltage to pulsating DC
Full wave rectifier conducts for both the half of the AC cycle
PN junction diode is used as a Switch ,rectifier .
Transistor is used as a switch in the saturation and cut off regions
Transistor is used as an amplifier in the active region
Transistor is a current controlled device
Diode is a unidirectional device
Transistor is a current controlled device
The three terminals of Transistor are namely emitter ,base and collector
LED means light emitting diode
UPS means uninterrupted power supply.
IC means integrated circuits
The output of OR gate connected to input of NOT gate results in NOR gate
The output of AND gate connected to input of NOT gate results in NAND gate
OR gate performs logical addition operation
AND gate performs logical multiplication
NOT gate is known as inverter
LED converts electrical energy to light energy
Free electrons are responsible for conduction