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Q1. | The most commonly used devices for differencing and amplification, in control systems, are |

A. | BJT amplifiers [Wrong Answer] |

B. | FET amplifiers [Wrong Answer] |

C. | operational amplifiers [Correct Answer] |

D. | either (a) or (b) [Wrong Answer] |

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Explanation:-
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**Also Read Similar Questions Below :**

⇒

Match the following:

List I (Microwave device) | List II (Application) | ||
---|---|---|---|

A. | Reflex Klystron | 1. | Wideband amplification |

B. | TWT | 2. | Very low power amplification |

C. | Cavity Klystron | 3. | Low power FM generation |

D. | Maser | 4. | Frequency multiplication |

A-1, B-2, C-3, D-4

A-4, B-3, C-2, D-1

A-3, B-4, C-1, D-2

A-3, B-1, C-4, D-2

⇒ The energy stored in a coil is 108 J. It is opened suddenly in 10 ms. The power dissipated instantaneously across the blades of switch is

108 W

1080 W

10800 W

108000 W

⇒ In a BJT CE amplifier circuit the value of coupling capacitor should be such that

its reactance is small for the lowest frequency in the input and output

its reactance is high for the lowest frequency in the input and output

its reactance is zero for the lowest frequency in the input and output

its reactance is infinite for the lowest frequency in the input and output

⇒ The range of a cordless telephone is about

1000 m

500 m

100 m

10 m

⇒ Find cut off wavelength for mode TE

_{11}in a circular waveguide having radius 2 cm. Assume K'

_{a}= 1.841

4 cm

6.82 cm

8 cm

68.2 cm

⇒ A transmission line having 50 Ω impedance is terminated in a load of (40 +

*j*30) Ω. The VSWR is

*j*0.033

0.8.+

*j*0.6

1

2

⇒ The velocity factor of a transmission line depends on

temperature

skin effect

relative permittivity of dielectric

none of the above

⇒ In equally tampered musical scale, an octave is divided into

12 intervals

10 intervals

7 intervals

5 intervals

⇒ Slotted line can be used for measurement of high frequencies

TRUE

FALSE

⇒ Kell factor is about

5

3

0.7

0.2

⇒ The units of transistor

*h*parameters

*h*

_{11}and

*h*

_{22}are the same.

TRUE

FALSE

⇒ The system shown in figure remains stable wh

k £ - 1

-1 < k < 1

l < k < 3

k > 3

⇒ Which one of the following statement is correct?

Both Laplace's (L) and Poisson's (P) equation are non linear

L is non linear but P is linear

L is linear but P is non linear

L, P both is linear

⇒ RF amplifiers are used in radio receivers for

better sensitivity

improved signal-to-noise ratio

better coupling of receiver to the antenna

all of the above

⇒ Which of the following is a passive component?

Semiconductor devices

Vacuum tube devices

Capacitors

All of the above

⇒ Binary multiplication 1 x 0 =

1

0

10

11

⇒ Consider the following

- Maximum energy of electrons liberated photoelectrically is independent of light intensity
- Maximum energy of electrons liberated photoelectrically varies nonlinearly with frequency of incident light.

(1) is true and (2) is false

(1) and (2) both are true

(1) is false and (2) is true

(1) and (2) both are false

⇒ In PCM, the quantization noise depends on

sampling rate

signal power

number of quantization level

signal energy

⇒ An instruction using immediate addressing mode in 8085 is

2 bytes long

3 bytes long

2 or 3 bytes long

1 or 2 or 3 bytes long

⇒ The characteristic impedance of coaxial cable is about

1000 ohm

500 ohm

250 ohm

75 ohm

⇒ In an intrinsic semiconductor, at a given temperature T

the number of electrons-hole pairs generated per second due to thermal motion are equal to the number of electron-hole pairs lost per second due to recombination

the number of electron-hole pairs generated per second due to thermal motion is always less than the number of electron-hole pairs lost per second due to recombination

the number of electron hole pairs generated per second due to thermal motion is always more than the number of electron-hole pairs lost per second due to recombination

any of the above

⇒ For a transfer function H(

*s*) = P(

*s*)/Q(

*s*), where P(

*s*) and Q(

*s*) are polynomials in

*s*

the degrees of P(

*s*) is always greater than degree of Q(

*s*)

the degree of P(

*s*) and Q(

*s*) are equal

the degree of P(

*s*) is independent of degree of Q(

*s*)

the maximum difference in degrees of P(

*s*) and Q(

*s*) is 1

⇒ Which device changes serial data to parallel data?

Counter

Multiplexer

Demultiplexer

Flip flop

⇒

**Assertion (A):** For elemental dielectrics, P = Na_{e}E_{i} where *N* is number of atoms/m^{3}, P is polarization, a_{e} is electronic polarization and E_{i} is internal electric field.

**Reason (R):** In elemental dielectrics there are no permanent dipoles or ions.

Both A and R are true and R is correct explanation of A

Both A and R are true but R is not correct explanation of A

A is true but R is false

A is false but R is true

⇒ ALU processes

decimal numbers

binary numbers

hexadecimal numbers

all of the above

⇒ A microwave junction is matched at all ports if the S matrix

has all diagonal elements zero

has all diagonal elements equal but not zero

has all diagonal elements complex

is Hermitian

⇒ The transistor of following figure in Si diode with a base current of 40 μA and I

_{CBO}= 0, if V

_{BB}= 6V, R

_{E}= 2 kΩ and β = 90, I

_{BQ}= 20 μA then R

_{B200 kΩ265 kΩ150 kΩ100 kΩ}

⇒ A single phase half wave controlled rectifier circuit has an R-L load. A freewheeling diode is also in the circuit. When freewheeling diode is conducting the SCR

is forward biased

is reverse biased

may be forward biased or reverse biased

forward biased initially but reverse biased afterwards

⇒ A step down cycloconverter has an input frequency

*f*. If it uses natural commutation, the output frequency

must be a sub-multiple of input frequency

can be any frequency

must be an even sub-multiple of input frequency

must be an odd sub-multiple of input frequency

⇒ An electromechanical device which actuates a train of step angular movements in response to a train of input pulses on one to one basis is

synchro control transformer

LVDT

stepper motor

tacho generator