Question with Answer BSNL JE

Q2. Two thin parallel wires are carrying current along the same direction. The force experienced by one due to the other is :

1. Parallel to lines
2. Perpendicular to the lines and attractive
3. Perpendicular to the lines and repulsive
4. Zero

Answer: B

Q3. 4mW of 0.5 micron radiation falls on a photo detector. If the quantum efficiency is 80 percent, the number of free charge carriers (electrons) generated per second would be :

1. 8 x 10 15
2. 8 x 10 16
3. 8 x 10 14
4. 8 x 10 9

Answer: C

Q4. In a feedback amplifier configuration, the output impedance of the amplifier (A) in the presence of feedback is :

1. Larger than the output impedance that would be there if the feedback was absent
2. Smaller than the input impedance that would be there if the feedback was absent
3. The same as that in the absence of the feedback
4. None of these

Answer: D

Q5. The intrinsic carrier concentration of silicon sample at 300 K is 1.5 x 10 16 /m 3 . If after doping, the number of majority carriers is 5 x 10 20 /m 3 , the minority carrier density is :

1. 4.50 x 10 12 /m 3
2. 3.33 x 10 4 /m 3
3. 5.00 x 10 20 /m 3
4. 3.00 x 10- 5 /m 3

Answer: B

Q6. A bidirectional thyristor without fate contact is also known by the name of :

1. SCR
2. SCS
3. SUS
4. Diac

Answer: D

Q7. A 4-bit UP/DOWN, binary ripple counter is initially reset to (0000). The UP/DOWN mode select input designated as U /D on the pin connection diagram of the IC is tied to HIGH level. What will be the counter output status after the first clock pulse.

1. 0001
2. 1000
3. 1111
4. None of these

Answer: B

Q8. The IC type number 74C00 belongs to :

1. Standard TTL logic family
2. High speed TTL family
3. CMOS family pin compatible with TTL
4. None of these

Answer: A

Q9. The slew rate of an opamp limits its large signal bandwidth and is measured in :

1. Volts per microsecond
2. Microvolts per second
3. Volts per degree Celsius
4. It is a dimensionless quantity

Answer: B

Q10. One of the following IC timer type numbers can be classified as a digital timer.

1. IC 555
2. IC 556
3. IC 558
4. 7240

Answer: D