AP ECET EEE 2019-9

1. The AND function can be realized by using only n number of NOR gates. What is n equal to

A. 2
B. 3
C. 4
D. 5

Answer : 3
Explanation:-

S.no	Gates	Number of NAND Gates Required	Number of NOR Gates Required
1	NOT	1	1
2	AND	2	3
3	OR	3	2
4	EX-OR	4	5
5	EX-NOR	5	4

2.When is the Ferranti effect on long overhead lines experienced?

A. The line is lightly loaded
B. The line is heavily loaded
C. The line is fully loaded
D. The power factor is unity

Answer : The line is lightly loaded
Explanation:-

3. Unit of reactive power is

A. VA
B. Watt
C. VAR
D. Ohm

Answer : VAR
Explanation:-
Unit of Active power=KW
Unit of Raective power=KVAR
Unit of Apparent power=KVA

4.The advantage of using a freewheeling diode with bridge type AC/DC converter is

A. regenerative breaking
B. relaible speed control
C. improved power factor
D. reduced cost of the system

Answer : improved power factor
Explanation:-

5.A 250 V DC generator is run at rated speed with no excitation. The open circuit voltage will be

A. Zero
B. About 2 to 3V
C. 100V
D. 250V

Answer : About 2 to 3V
Explanation:- 2-3V is generated due to residual magnetism of poles

6. Transformers are rated in KVA instead of KW because_________________

A. Load power factor is often not know
B. KVA is fixed where KW depends on load pf
C. Total transformer loss depends on volt-amperes
D. It has become customary

Answer : Total transformer loss depends on volt-amperes
Explanation:-

7. Transmission lines are transposed to ______________

A. reduce corona loss
B. reduce skin effect
C. prevent interference with neighbouring telephone lines
D. prevent short circuit between any two lines

Answer : prevent interference with neighbouring telephone lines
Explanation:-

8.Which one of the following materials cannot be used for permanent magnets?

A. Alnico
B. barium ferrit
C. Carbon steel
D. Iron cobalt alloy

Answer : Iron cobalt alloy
Explanation:-

9. Diversity factor is the ratio of_______________

A. Sum of maximum demands of consumers/system maximum demand
B. maximum demand of consumers/average demand
C. demand of all consumers/average demand
D. Average demand/system maximum demand

Answer : Sum of maximum demands of consumers/system maximum demand
Explanation:-

10.The 8051 has _______________16-bit counter/timers

A. 1
B. 2
C. 3
D. 4

Answer : 2
Explanation:-