DFCCIL Recruitment 2021
Dedicated Freight Corridor Corporation of India Limited (DFCCIL) Public Sector Undertaking under the administrative control of the Government of India (Ministry of Railways).DFCCIL has released the official notification for the recruitment of 1074 vacancies for the recruitment of Junior Executives, Executives, and Junior Managers through their official website, i.e. dfccil.com.
26 SEPT TO 30 SEPT
DFCCIL’21 EE: Daily Practices Quiz
DFCCIL’21 EE: Daily Practices Quiz 21-Sep-2021
Each question carries 1 mark.
Negative marking: 1/4 mark
Total Questions: 06
Time: 08 min.
Q1. What is the relationship between the line voltage and the phase voltage in a delta -connected load?
(a) Line voltage = Phase current
(b) Line voltage > Phase voltage
(c) Line voltage < Phase voltage
(d) Line voltage = Phase voltage
Q2. An eight-pole wound rotor induction motor operating on 60 Hz supply is driven at 1800 rpm by a prime mover in the opposite direction of revolving magnetic field. The frequency of rotor current is:
(a) 60 Hz
(b) 200 Hz
(c) 120 Hz
(d) 180 Hz
Q3. A P– type crystal is obtained by doping
1. silicon with arsenic,
2. silicon with aluminium,
3. Ge with boron,
4. Ge with phosphorus.
(a) 2 and 3 are correct
(b) 2 and 4 are correct
(c) 1 and 4 are correct
(d) 1 and 3 are correct
Q4. The emf induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be:
(a) 620 V
(b) 580 V
(c) 600 V
(d) 640 V
Q5. In an induction motor, if the rotor resistance is equal to stand-still reactance then the maximum torque is…………
(a) Less than starting torque
(b) Equal to starting torque
(c) More than starting torque
(d) None of the above
Q6. Assertion (A): Shunt of an ammeter has a low resistance.
Reason (R): Shunt may be connected in series or parallel with ammeter.
(a) Both A and R are true and R is correct explanation of A
(b) Both A and R are true, but R is not correct explanation of A.
(c) A is true, R is false
(d) A is false, R is true
Sol. In delta connected system the line voltage is equal to the phase voltage and the Line current is √3 times of Phase Current.
= 900 rpm
Now it is rotating in opposite direction so slip (S) = (900-(-1800))/900=3
Rotter frequency (Fr) = Sf
= 180 HZ
Sol. Doping means the introduction of impurities into a semiconductor crystal to the defined modification of conductivity. In P-Type Semiconductor, the addition of trivalent impurities such as boron, aluminium or gallium to an intrinsic semiconductor creates deficiencies of valence electrons, called “holes”.
Sol. For generator, V_t=E_g-I_a R_a=600-(200×0.1)=580 V.
Sol. At maximum torque: slip(s)=R_2/X_2
If R_2=X_2, then s=1(starting slip)
So, if in an induction motor, if the rotor resistance is equal to stand-still reactance then the maximum torque is equal to starting torque.
Sol. Shunt is connected in parallel with ammeter and has low value of resistance.