TS ECET EEE 2016-7

1. A Step down dc chopper has an input voltage V.If duty cycle is 'a 'and the load is resistive, the rms value of output voltage is

A. α V
B. √a V
C. a^2 V
D. (1-α) V

Answer : √a V
Explain:-

2. Abridge type single phase cyclo-converter changes the frequency f to f/3. Then one half wave of output contains

A. Three full waves of input
B. Three half waves of input
C. Six full waves of input
D. Six half waves of Input

Answer : Three full waves of input
Explain:-

3. Internal RAM Size of 8051 microcontroller is _____ bytes

A. 128K
B. 4K
C. 128
D. 64k

Answer : 128
Explain:-

4. A separately excited dc motor is fed from a 500 V dc through a one quadrant chopper, Resistance of the armature is 0.1 ohm and armature current is 200 A.The voltage constant is 1.4 VIA-rad/sec. If the field current is 2A and the duty cycle of the chopper is 0.5, find the speed in rad/sec

A. 82.14
B. 90.14
C. 72.14
D. 100.14

Answer : 82.14
Explain:-

5. An electric heater draws 1000 W from a 250 V source. If it is connected across a 125 V source then the power drawn by this heater will be

A. 500 W
B. 250 W
C. 1000 W
D. 125W

Answer : 250 W
Explain:-

6. Which of the following is the best conductor

A. carbon
B. copper
C. Tungsten
D. iron

Answer : copper
Explain:-

7. The best suitable material for heating element is

A. Manganin
B. Constantan
C. Nichrome
D. Carbon

Answer : Nichrome
Explain:-

8. Beyond curie point ferro magnetic material

A. Has increased flux densities
B. Losses its magnetic properties
C. becomes very hot
D. will have a slight bend

Answer : Losses its magnetic properties
Explain:-

9. A star arrangement of resistances has each resistance of 3ohm. The equivalent delta arrangement will have each resistance value of

A. 1ohm
B. 9ohm
C. 3ohm
D. 6ohm

Answer : 9ohm
Explain:-

10. When 'n similar resistors each of resistance 'r'are connected in parallel the total resistance is 'R'. If these resistances are connected in series, the total resistance is

A. nR
B. R/n²
C. n²R
D. R/n

Answer : n²R
Explain:-