AP ECET EEE 2019-1

1. Which of the following is not a conducting material

A. Copper
B. Tungsten
C. Germanium
D. Platinum

Answer : Germanium
Explanation:- Copper,Tungsten and platinum are good conducting materials so Germanium is not a conductiong material,it is semi conductor material

2. For a given dielectric, with increase in temperature the Ionic polarizability

A. Increases
B. Decreases
C. Remains same
D. Fluctuates

Answer : Remains same
Explanation:-

3. Advantages of Improved power factor are

A. Increase in Operating efficiency of the power system
B. Improvement in Voltage Regulation
C. Reduction in overall cost per Unit
D. Better Utilisation of KW capacities of the prime movers, transformers, switch gear and lines

Answer : Better Utilisation of KW capacities of the prime movers, transformers, switch gear and lines
Explanation:-

4. The current transformer has a phase error of +3° . The phase angle between primary and secondary currents is

A. 3°
B. 177°
C. 180°
D. 183°

Answer : 177°
Explanation:-
Given Phase error = 3°
Phase angle between primary and secondary currents = 180°-Phase error
= 180°-3°= 177°

5. Tractive effort of an electric locomotive can be increased by

A. Using Low output motors
B. Increasing the supply voltage
C. Decreasing dead weight over the driving axles
D. Using High output motors and increasing dead weight over driving axles

Answer : Using High output motors and increasing dead weight over driving axles
Explanation:-

6. Specific energy consumption becomes

A. More when distance between stops is more
B. More with higher values of acceleration
C. More with the high train resistance
D. Less with the increase in crest Speed

Answer : More with the high train resistance
Explanation:-

7. Commutation overlap in the phase-controlled AC to DC converter is due to

A. Load inductance
B. Harmonic current of load current
C. Switching operation in the converter
D. Source Inductance

Answer : Load inductance
Explanation:-

8. If the frequency of the transmission system is changed from 50Hz to 100Hz, the string efficiency is

A. Will increase
B. Will decrease
C. remain unchanged
D. may increase or decrease depending on the line parameters

Answer : remain unchanged
Explanation:- String efficiency does not depends on frequency of system

9. The maximum power will be transferred from a voltage source to a load when

A. the source impedance is half that is the load impedance
B. the source impedance is equal to that of the load impedance
C. the source impedance is twice that of the load impedance
D. both source and load impedance must be zero

Answer : the source impedance is equal to that of the load impedance
Explanation:- According to the Maximum power transfer theorem, the maximum power is delevered to load when the source impedance is eqaul to the load impedance

10. Trapezoidal speed time curve pertains to

A. Main line service
B. Urban service
C. Sub urban service
D. Urban/Suburban service

Answer : Main line service
Explanation:-
Trapezoidal speed time curve--Main line service
Quadrilateral speed time curve -- Urban/suburban service