multtiple choices

electronics questions

32)In an op amp -------- is the maximum rate of change of output voltage
a) input bias current b) slew rate c) CMRR d) NONE
33) ----------- is the input voltage which must be applied across the input terminals of an op amp to obtain zero input voltage
a)input offset voltage b) input bias current  c)slew rate d) NONE
34) in an ideal op amp input impedance is ---------------
a) zero b) infinite c)finite d) none
35)a ---------- is a semiconductor device that converts light into current
a)LDR b)photodiode c) optocoupler d) phototransistor
36) universal flipflop is ------------
a) JK flipflop b) D flipflop c)SR flipflop d)T flipflop
37)the 2 possible states of multivibrators  are
a)Q1 on Q2 OFF  b) Q1 OFF Q2 on c) both a and b  d) Q1 ON Q2 on
38)------------ is a digital circuit that is able to count the number of pulses that are applied to its input terminals
a) counter b) flipflop c) logic gate d0 none
39)transistor biasing represents -----------
A)ac  b)dc c) both ac and dc d) none
40)An oscillator differs from an amplifier because it -------------
a) has more gain b) requires no input signal c) requires no dc supply d0 none
41) emitter follower is used for ----------
a) Current gain b) impedance matching c) voltage gain d) none
42)the output impedance of emitter follower is
a) high b) very high c) slightly d) low
43)the collector of a transistor is --------- doped
a)moderately b) highly c)slightly d)none
44)to shift waveform either above or below a given voltage without destroying the waveform
a) clipper b) clamper c)integrater d) differentiar

45)diode and resisters are required for
a) clipper ckt  b)clamper ckt  c) integrater d) differentiar
46)An example of a weighted code
a)BCD  b)ASCII c) Excess 3 code d) grey code
47) ----------is the uncertainity of output state , when clock pulse is too large
a)race around condition b) overflow c) propagation delay d)none
48)the radix\base of a octal number system is
a)2  b) 4  c)8  d) 16
49)the binary equalent to decimal number 12is -----------
a)1011 b)1100  c)1101  d)1010
50)LED is a ----------------
a)transistor b) DIAc c) diode d) UJT

communication questions

1. Modulation index for FM can be………………..unit.

a) greater than b) less than c) equal to d) zero

2. The maximum peak to peak voltage of an AM wave is 16mV and the minimum peak to peak voltage is 4mV. Calculate the modulation factor.

a) 50% b) 60% c) 30% d) 66%

3. The DC output of a power supply is 12V at no load and 11V at full load. Calculate the percentage of load regulation.

a) 83% b) 0.83% c) 9.09% d) 0.909%

4. Calculate the backup for an system UPS. Load is the usage power. Suppose we are working a PC, then the load is around 300W. Power factor varies for device to device. The average power factor is 1.4. Voltage of the battery is 12V in each battery, battery Ah used for the UPS is 7.

a) .178 hours b) .198 hours c) .188 hours d) .168 hours

5. The speed of rotating magnetic field in the stator, Ns:

a) 120F   b) 120   C)120FP d) 120P

        P            FP                           F

 6). Calculate synchronous speed of a rotating magnetic field having 2 poles.

a) 3000 b) 2000 c) 6000 d) 5000

7. Base of the octal number system is………….

a) 2 b) 7 c) 8 d) 16

8. Convert (110110)2 into decimal.

a) 55 b) 54 c) 52 d) 51

9. Convert (783)10 to hexadecimal.

a) 30E b) 3015 c) 3014 d) 30F

10. (110101)2 + (1011)2 is…………..

a) (1000001)2 b) (100001)2 c) (10000001)2 d) (100100)2

11. 9’s complement of 454 is………

a) 999 b) 454 c) 544 d) 545

12. Belt used in flour mills is-----------

a) V belt b) circular belt c) rope belt d) Flat belt

13. A.A ̅ is………

a) A b) 1 c) 0 d) ̅A

14. A force of 30N is requiredto move a body of mass 35Kg on a flat horizontal at constant velocity .find coefficient of friction (take g=10m/s²⁾?

a) 315Nb) 356N c) 355Nd) 350N

15. A horizontal force of 100N is required to slide a sledge weighing 50kgF over a flat surface. Calculate co-efficient of friction. (Take g=9.8 m/s² )

a) 0.204b) 0.24c) 0.304 d) 24

16. Rahul bought a book for Rs. 250/- and sold it for Rs. 340/-. Find his profit % or loss %?

a) 26.47% b) 36% c) 100% d) 73.53%

17. If a chair was sold for Rs. 1250/- at a loss of Rs. 220/-, find the cost price of the chair?

a) Rs. 1030/- b) Rs. 1470/- c) Rs. 1100/- d) Rs. 1300/-

18.vertical component of a force P which makes an angle α with the vertical is given by.....................

a)Fy=P Sin α b) Fy=P Cos α c) Fy=P Sec α d) Fy=P Cosec α

19. The kind of equilibrium in which the position of centre of gravity is not disturbed is called…………

a) Stable b) unstable c) neutral d) none of these

20. What is the resultant of two unlike parallel forces of 25N?

a) 50 b) 0 c) 625 d) 1

21. Two forces having magnitude 5N and 8N act at apoint at angle of 45⁰ b/w them .Find the resultant forces?

a) 11 N b) 11.04N c) 12 N d) 12.04N

22. A force equal and opposite to the resultant of the force acting on a body is called…………..

a) Equivalent force b) Equilibriant c) Equal force d) Equipotential force

23. Meera bought a scientific calculator for Rs. 850/- and sold it for Rs. 600/-. Find her profit % or loss %?

a) 70.6% b) 41.6% c) 29.4% d) 23.5%

24. The maximum value of the frictional force before the body just slides over the surface of another body is called………….

a) Static b) Limiting c) Co-efficient d) Dynamic

25. 2’s compliment of 11001100 is----------

a) 00110100 b) 00011100 c) 00101011 d) 00110010

electronic mechanic objective questions

1. velocity of radio waves is……………. a) 300m/s  b)3*10³m/s c)3*10⁸ d)30*10⁸m/s

2. line of sight propagation is also known as …………………a)ground wave  b)space wave c) sky wave d)ground  reflected wave

3. ………….frequency is used in ground wave propagation a)UHF  b)HIGH c)  LOW   d)MEDIUM

4. Q point of antenna will depend up on…………..of antenna  a)length   b) outside diameter  c)wavelength   d)inside diameter

5. broadcasting frequency for AM is…………………… a) 550-1600HZ  b) 540-1600KHZ  c)88-108MHZ d)455-1500KHZ

6. broadcasting frequency for FM is……………………… a) 88-100HZ  b) 88-108KHZ  c)88-108mHZ d)88-108MKHZ

7. IF frequency for AM is……………… a) 455KHZ  b) 455MHZ  c)540KHZ d)500HZ

8. IF frequency for FM is……………… a107HZ  b) 10.7KHZ  c)10.7MHZ d)88MHZ

9. mixer stage is consist of……………. a)RF&LO b)IF&LO c)RF&IF d)RF&AGC

10. AGC  is stands for……………. a)automatic gain constant b)amplitude gain control c)amplitude gain constant d)amplitude gain control

11. number of side band in FM is…………..   a) 2    b)4    c)1   d)infinity

12. FM is/are used……………type/s of antenna a) VHF     b)UHF   c)BOTH 1&2   d)HF

13. pre emphasis and deemphasis used in………….modulation a)AM    b) FM   c)PM    d)ASK

14. the ability of radio receiver producing suffiecient AF ouput even for week RF signal a)sensitivity   b)selectivity        c) fidility     d)s/n ratio

15. hertz antenna width is…………..    a)λ    b) λ/2 c) λ/4 d)2 λ

16.solder contain………….. a)lead-40,tin-60   b) lead-50,tin-5 0   c) lead-60,tin-40    d) lead-40,tin-40  

17. …………type of flux used for soldering electronic component  a)flux    b)rosin   c)lead    d)tin   

18. ESD means……………. a)electronic standard defelction    b) electro static difference    c) electronic static difference   d) electro static discharge

19. CRO displays …………. a) b) c) d)

20. DSO  is stands for…………………… a) b) c) d).

21. CRO uses …………… a) b) c) d)

22. CRO flurosent screen uses th e phosphorous isotope is………..   a)flux   b)rosin   c) d)

23. in IC 8051 contain …………pins a) b) c) d)

24. in 8051 contain………….address bits a) b) c) d)

25. ALE means…………… a) b) c) d)

26. ……………….oscillator is used in 8051 a) b) c) d)

27. in 8051 contain…………..data bits a) b) c) d)

28. oscillating frequency in microcontroller is………….. a) b) c) d)

29. MOV A, R4 is an example for…………….. a) b) c) d)

30. MOV A,#DATA is an example of……………. a) b) c) d)

31. …………..ports are in 8051 a) b) c) d)