Important Paper Electrical Engineering

1. Three identical impedance are connected in delta to 3 phase supply of 400 V. The line current is 34.65 A and the total power taken is 14.4 kW. What is the resistance of the load in each phase ?
(1) 20         
(2) 16
(3) 12          
(4) 10              
Ans (3)
2. In three phase 400 volt, 50 Hz supply, the phase to neutral voltage is
(1) 220 Volt   
(2) 230Volt
(3) 440Volt     
(4) 150Volt               
Ans  (2)   
3. Each branch of Y-connected load has resistance to 10𝛺 The resistance of each branch of an equivalent  𝛥-connected load will be
(1) 30 𝛺        
(2) 100 𝛺
(3) 110 𝛺       
(4) None of these     
Ans  (1)
4. In 3 phase system with what degree there is a phase displacement between different phases ?
(1) 360°          
(2) 220°
(3) 180°        
(4) 120°             
Ans  (4)
5. Which three phase system does not contain neutral ?
(1) Star   
(2) Delta
(3) Both do not contain 
(4) Both (Star and Delta)                 
Ans (2)
6. In a three phase four-wire system the line voltage is 400 V and a load of 10 kW is connected between line conductor and the neutral. The current through the load is :
(1) 40 A        
(2) 25A
(3) 43.5 A       
(4) 14.45 A           
Ans  (3)
7. To calculate the power factor which of the following is odd one :
(1) True power       
(2) P/VI
(3) R/Z        
(4) V/I               
Ans  (4)
8. Unit of reactive power is :
(1) Watt       
(2) Kiol watt 
(3) VAR         
(4) Volt ampere .                
Ans  (3)
9. When XL is equal to XC :
(1)  Z = R        
(2) Z = XC
(3) Z = XL          
(4) None of these               
Ans  (1)
10. At resonance , inductive reactance is equal :
(1) Resistance        
(2) Capacitance
(3) Capacitive Reactance        
(4)  Inductance             
Ans  (3)